Can 1^x=2?

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  • Опубликовано: 11 дек 2024

Комментарии • 2,7 тыс.

  • @blackpenredpen
    @blackpenredpen  Год назад +221

    Can e^e^x=1?
    Sol here ruclips.net/video/ckc9F0VjZ3k/видео.html

    • @69Gigantosaur
      @69Gigantosaur Год назад

      Hello😊

    • @JustAPersonWhoComments
      @JustAPersonWhoComments Год назад +7

      You can take the natural logarithm (ln) of both sides:
      ln(e^(e^x)) = ln(1)
      Using the property that ln(e^a) = a:
      e^x = 0
      Now, you have e^x = 0, which has no real solutions because you cannot raise a positive number (e) to any power and get 0.

    • @dragondg6412
      @dragondg6412 Год назад +7

      e=0 x=1 easy
      0^0^1=1

    • @Mono_Autophobic
      @Mono_Autophobic Год назад +39

      ​@@dragondg6412bro studied from kfc toilet 💀

    • @ajb16384
      @ajb16384 Год назад +8

      ​@@dragondg6412bro graduated from the 15 year old marker board in social studies

  • @Isometrix116
    @Isometrix116 3 года назад +10133

    Imaginary numbers are the math equivalent of going into the shadow dimension to get through obstacles

  • @brenn7754
    @brenn7754 3 года назад +8423

    When blue pen gets in involved, you know it's serious...

    • @bombdog3973
      @bombdog3973 3 года назад +44

      Good one xd

    • @WerewolfLord
      @WerewolfLord 3 года назад +214

      Really serious is the purple pen.

    • @GianniCampanale
      @GianniCampanale 3 года назад +232

      @@WerewolfLord you don't want to see the purple pen

    • @godson200
      @godson200 3 года назад +63

      @@GianniCampanale purple is for thanos

    • @brenn7754
      @brenn7754 3 года назад +45

      @@godson200 this was blackpenredpen infinity war. Next is blackpenredpen endgame...

  • @jamesfleming4919
    @jamesfleming4919 3 года назад +5889

    “360, but we are adults so we use 2pi” I felt that

  • @alex_marr
    @alex_marr Год назад +172

    Notice that 1^x = 2 and 1 = 2 ^(1/x) are, actually, two diffferent equations with different domain of x. You solved the second equation and not the first one. Edit: that is EXACTLY why wolfram can solve the second one.

    • @zenedhyr7612
      @zenedhyr7612 11 месяцев назад +10

      To simplify:
      {1^x-2=y, y=0} ≠ {1-2^(1/x)=y, y=0}
      Similar example:
      x^2-1=0 and x-sqrt(1)=0 will give different graph. [Search on google]
      x^2-1=0
      x^2=1
      x=sqrt(1)
      x-sqrt(1)=0 ■

    • @vaarmendel1657
      @vaarmendel1657 11 месяцев назад +3

      1) x real -> No solution. OK
      2) Let's suppose x complex -> x = a + ib (a, b Real numbers !)
      -> 1^x = 1^(a + 1^ib) = 1^a . 1^ib
      = 1 . 1^ib = 1^ib
      Applying ln on complex numbers: ln(z) = ln|z| + i arg(z), we get :
      ln (1^ib) = ln|1| + ib = 0 + ib = ib
      Hence ln(1^x) = ib = ln(2). Pure imaginary = pure real -> Impossible. x is not a complex number
      Solution: NO SOLUTION.
      What about that ?

    • @xinpingdonohoe3978
      @xinpingdonohoe3978 7 месяцев назад +4

      ​@@vaarmendel1657 close, but the issue is you've used the wrong definition of arg(z). arg(z) requires base e, not base 1. So ln(1^ib)=ln(e^(2πni×ib))
      =ln(e^2πkb)=2πkb. Then 2πkb=ln(2) has solutions for b.

    • @rodabaixo13
      @rodabaixo13 6 месяцев назад +3

      ​@@zenedhyr7612bro forgot the plus or minus. Ofc x^2-1 is different from x-1. Its not just about degree. The solutions arent even the same like equivalent equations. Thats just blatant nonsense

    • @robertveith6383
      @robertveith6383 14 дней назад

      ​@@vaarmendel1657-- The exponent ib must be inside grouping symbols.

  • @AethernaLuxen
    @AethernaLuxen Год назад +395

    I like how this whole time he was holding a poke ball and half of us were too busy having our brains crushed to realise

    • @IONProd
      @IONProd Год назад +49

      It's actually his mic (in case you didn't notice)

    • @j03man44
      @j03man44 Год назад +4

      WTF 😮

    • @takvacs
      @takvacs Год назад +17

      Isn't that usual though? He has it in every video

    • @Shikogo
      @Shikogo Год назад +4

      I clicked the video because of the Pokeball lmao

    • @The_Red_Scare
      @The_Red_Scare Год назад +1

      I actually noticed immediately and soon figured that it must be either his mic (somehow) or a random thing he holds as a gag for all his videos.

  • @stephenbeck7222
    @stephenbeck7222 3 года назад +4609

    “We need two things. The first thing is the distance. The next thing is to erase the equal sign better. The third thing is the angle.”

    • @blackpenredpen
      @blackpenredpen  3 года назад +518

      Lol

    • @lordmomstealer
      @lordmomstealer 3 года назад +79

      @@blackpenredpen I have question for you
      4^x+6^x=9^x
      FIND THE VALUE OF X

    • @lordshen3078
      @lordshen3078 3 года назад +180

      @@lordmomstealer haha dude this is video by mind ur decisions

    • @talkgb
      @talkgb 3 года назад +68

      @@lordmomstealer very basic u = 2^x and v = 3^x substitution

    • @TheHashimq
      @TheHashimq 3 года назад +32

      @@lordmomstealer this is from mind your decision
      He would do it in minutes

  • @randomyoutubecommenter4
    @randomyoutubecommenter4 3 года назад +7844

    "Can 1^x = 2?"
    - No.
    *video ends*

    • @abhaysharmafitness
      @abhaysharmafitness 3 года назад +130

      x=log base 1 of 2

    • @Pirater666l
      @Pirater666l 3 года назад +352

      @@abhaysharmafitness log base 1 of 2 = indefinite, so no

    • @korayacar1444
      @korayacar1444 3 года назад +95

      @@abhaysharmafitness no such thing as log base 1

    • @ramg4699
      @ramg4699 3 года назад +55

      @@Pirater666l *indefinite in real numbers

    • @seroujghazarian6343
      @seroujghazarian6343 3 года назад +23

      @@korayacar1444 yes there is, in the complex world.

  •  3 года назад +3101

    My man starting to look like an ancient philosopher who lives on a mountain, I dig it

  • @dr.downvote
    @dr.downvote 3 года назад +958

    Mathematicians whenever they wanna look complicated : Let's talk about complex numbers
    Physicists whenever they wanna look complicated: let's talk about Quantum physics.
    Chemists whenever they wanna look complicated : let's talk about chemistry!

    • @KBMNVLpNdLumkstz
      @KBMNVLpNdLumkstz 3 года назад +99

      To be fair, modern chemistry based on quantum physics

    • @magmar-wt5on
      @magmar-wt5on 2 года назад +50

      And QM involve hilbert space so everybody talks about complex number 😂

    • @aabahdjfisosososos
      @aabahdjfisosososos 2 года назад +5

      Chem is not hard

    • @avy1
      @avy1 2 года назад +59

      Chemistry is applied quantum mechanics, quantum mechanics is applied mathematics. And as always, math is king.

    • @pf32900
      @pf32900 2 года назад +9

      Complex numbers? Why not quaternions, octonions, sedenions and the Clifford algebras?

  • @ultrio325
    @ultrio325 3 года назад +46

    He went from:
    guys I have pen and I do math
    to:
    筆子曰:「無實數解既找虛數解」。

    • @yehe297
      @yehe297 3 года назад +2

      "no real number solution then go find complex number solution"

    • @shinobi5189
      @shinobi5189 9 месяцев назад

      @@yehe297doing gods work

  • @iQKyyR3K
    @iQKyyR3K 3 года назад +2609

    That felt like a mathematical crime.

    • @twakilon
      @twakilon 3 года назад +180

      Nah. It's perfectly legal, as long as you DON'T consider the wrong logarithm branch.

    • @bagochips1208
      @bagochips1208 3 года назад +65

      More like exploiting loopholes

    • @twakilon
      @twakilon 3 года назад +80

      @@bagochips1208 it's not a loophole though. The problem lies in the argument function.

    • @angelmendez-rivera351
      @angelmendez-rivera351 3 года назад +180

      @KiwiTV It doesn't defeat itself. It just happens to be inconvenient for humans. Mathematics has never been intuitive, though. Human brains didn't evolve to be able to easily deal with complex numbers. They evolved so that we could do 3rd grade elementary school arithmetic. Everything else is just us making ourselves more miserable against our own evolution for the sake of additional benefits.

    • @WorkinDuck
      @WorkinDuck 3 года назад +144

      @KiwiTV Complex Numbers allow us to solve real word phenomenons, like apparent/reactive power in electrical systems, pretty elegant. It doesn't defeat itself, it only offers multiple perspectives of a problem

  • @mrhatman675
    @mrhatman675 3 года назад +3889

    You are evolving into one of these chinese big beard philosophers lol

  • @Kdd160
    @Kdd160 3 года назад +1883

    "I don't like to be on the bottom, I like to be on the top."

    • @samarth.suthar
      @samarth.suthar 3 года назад +75

      Now that's what everyone wants to be... Underrated comment...

    • @Barocalypse
      @Barocalypse 3 года назад +25

      "i don't like to be on the bottom, i like to be on the top."*

    • @MrDerpinati
      @MrDerpinati 3 года назад +14

      *mm nice*

    • @akmalfaiz7094
      @akmalfaiz7094 3 года назад +44

      That phrase leads to two different endings

    • @gani9176
      @gani9176 3 года назад +8

      We got the same surname😂

  • @robinbrowne5419
    @robinbrowne5419 3 года назад +135

    I would guess 2 possibilities:
    1. No. 1^x cannot equal 2.
    2. If 1^x can equal 2, then 1^x can equal anything, because there is nothing special about 2.

    • @speedyx3493
      @speedyx3493 2 года назад +51

      The 1st one is correct :) 1^x will ALWAYS equal 1, even if x is a complex number. The video is just tricking you, it’s like those old 1=2 videos when the guy slily hides the fact that he is breaking the math axioms somewhere

    • @glitchy9613
      @glitchy9613 Год назад +7

      @@speedyx3493 Both possibilities are wrong, the 3rd correct possibility that 1^z can have a countably infinite amount of solutions (not indeterminant like 0/0), but only when z is not rational.

    • @xinpingdonohoe3978
      @xinpingdonohoe3978 Год назад +13

      @@glitchy9613 I feel you're misunderstanding his point. He's saying 1^x can equal anything given a sufficient value of x. And by branches, it's correct.
      1^x=y, take the right branch and you can get x=ln(y)/2πni. Maybe take different branches of the ln(y) and you'll get even more solutions.
      The exception will be 0. Branches don't matter, taking a logarithm of 0 will cause some sort of issues. Maybe on a Riemann sphere you can argue it, but even then not necessarily.

    • @glitchy9613
      @glitchy9613 Год назад +3

      ​@@xinpingdonohoe3978 he literally says "1^x will ALWAYS equal 1" I doubt that was his point

    • @xinpingdonohoe3978
      @xinpingdonohoe3978 Год назад

      @@glitchy9613 I reread my thing, and I can only assume I wasn't referring to Speedy Gonzales here. I think I was referring to BPRP, just from where I stand.
      Sure, for each x it is true that 1^x can equal 1, but for complex x, 1^x may be something else too.

  • @Nino-eo8ey
    @Nino-eo8ey Год назад +14

    After finally having learnt complex numbers, it feels so good being able to understand these types of videos! Keep up the great work.

  • @McNether
    @McNether 3 года назад +1115

    Actually Wolfram-Alpha is correct. Too understand why we will need some function-theory/complex analysis (for example: Complex Analysis, Elias M. Stein S. 97-100). At first we will need a definition of z^w with w,z in C. For any z in C\(-∞,0] we can define a function
    z^: C --> C by z^w:=exp(log(z)•w) where log is the principal branch of the logarithm (that means that log(1)=0). Of course you can choose another branch but in this case the definition does not match with the exponetialfunction with a real basis.
    Using this definition we get:
    1^x =exp(log (1)•x)=exp(0•x)=1 which states that the equation
    1^x = 2 got no solution.
    Now we take a look at the Question: "Can we finde a x in C such that 2^(1/x)=1?"
    Using the definition we get
    2^(1/x)=exp(log (2)•(1/x))
    which is equal to 1 whenever log (2)/x=2πi•k, for any k in Z. This gives the solutions you are getting too.
    After clearing this we should talk about the "contradiction" at 06:23. What you are writing there is correct but its not a contradiction to the above:
    1^x=2 => 1=2^(1/x) means "every solution of the first expression is also a solution of the second Expression" (which is correct cause the left expression got no solutions).
    The other direction 1^x=2 x²=1 is correct but
    x²=1 => x=√1 is wrong (the solutions -1 "gets lost").
    And this gets even "worst" when complex numbers are involved...

    • @writerightmathnation9481
      @writerightmathnation9481 3 года назад +166

      The main error is conflation of the notion of a function with the notion of a relation, by using what are sometimes referred to in complex analysis books as "multi-valued" functions. There is no such thing. A function, by definition, is decidedly NOT "multi-valued". This leads to an aberration involving a failure to understand how equal signs work in a coherent presentation of mathematics. There are two fundamental ways they can be used coherently, and all other coherent uses are definable from these.
      (a) The main fundamental semantic use of an equal sign is to write a mathematical statement that is interpreted as true in the context of some given model of some theory because it pertains to the facts in that context, AND that statement that is interpreted as true in that context BECAUSE the one and only thing that is described to the left of that equal sign is exactly the same thing in that model as the one and only thing described to the right of that one and the same equal sign. This is written to convey clearly to the reader some accurate information about the context provided by the given model. Mistakes can be forgiven, but persistent incoherent abuses of notation should be excised from mathematical vocabularies.
      (b) The main fundamental syntactic use of an equal sign is to write a mathematical statement that is to be tested for truth in the context of some given model or class of models of some theory because it pertains to the facts in that context, AND that statement that is an hypothetically testable assertion in that specific context BECAUSE the descriptions to the left and right of that particular equal sign are interpretable in the context of the model or class of models to be considered, and the question of whether some model or class of models satisfies that particular statement is a coherent question in that context. Such a syntactic use of an equal sign is written to convey clearly to the reader some problem (i.e. it is a mathematical query) aimed to elicit some accurate information (a clearly formulated and completely explained solution of the problem and answer to the question) about the context provided by the given model or class of models. Mistakes can be forgiven, but persistent incoherent abuses of notation should be excised from mathematical vocabularies.
      Sensationalism should be rooted out and excised, just like incoherent abuses of notation should be. Otherwise, we our logic system will prove absurdities like 0=1 in the real number system. A logical system that allows such nonsense is not useful, because from such things, the notion of "provable equation" and "equation" are indistinguishable. By a variant of Occam's Razor, we should not invent a terminology that pretends to distinguish things that are indistinguishable.

    • @nicktravisano7152
      @nicktravisano7152 3 года назад +236

      bruh what

    • @stochasticks
      @stochasticks 3 года назад +86

      ​@@nicktravisano7152 There's a distinction between log applied as a function and the relation called the inverse image of a point in a space via a function. Both are relations between elements of sets but a function has the property that if x=y then fx=fy . The relation named "inverse image" has not in general such property. What blackpen writes on the board is formally incorrect. You cannot use the equal sign if applying something which is not a function on both sides of the equation, such writing down "log" but in fact meaning inverse image of the exponential function in the complex plane. The apparently revolutionary results you find in the complex plane are not so much revolutionary but abuses of the inverse relation treated as a function when it should not be. Still fun though.

    • @HDitzzDH
      @HDitzzDH 3 года назад +102

      tf am I reading

    • @degeestvanpeterrdevries3366
      @degeestvanpeterrdevries3366 3 года назад +216

      @@HDitzzDH University students having a discussion

  • @blackpenredpen
    @blackpenredpen  3 года назад +1429

    Can 0^x=2?

    • @namantenguriya
      @namantenguriya 3 года назад +42

      Love you from India 🥰🥰

    • @davinderSingh-zr1hu
      @davinderSingh-zr1hu 3 года назад +130

      Nah

    • @robrazzano9168
      @robrazzano9168 3 года назад +294

      No. Ln 0 is undefined, and r=0 on the complex plane, so you are always stuck dividing by zero.

    • @redstoneplayz09
      @redstoneplayz09 3 года назад +25

      If you do it the way you did it, I get:
      x = ln(2)/(ln(0))
      and ln0 is ln(0) + i*n
      Maybe if there is a different way it's possible but not with how you did it in the video.

    • @LuVD990
      @LuVD990 3 года назад +1

      I came back to your channel. It is so funny the topics related.

  • @HourRomanticist
    @HourRomanticist 3 года назад +179

    You know what. This came in my recommended, and man let me tell you, my algebra 2 teacher must be doing a great job because I don't know how I willingly clicked on this and was genuinely interested lol

  • @geometrividad7716
    @geometrividad7716 3 года назад +33

    This is very similar to the equation sqrt(x)=-1. If you put that into Wolfram, it will tell you that it has no solutions. You can try to argue that well, actually, one of the square roots of 1 is -1, but the thing is that's not what sqrt(_) actually is. The same is true under complex exponentiation: the principal branch is used by definition and as such, 1^x=1 no matter which x you plug in.
    As others have pointed out, this does not contradict that 2^(1/x)=1 does have solutions in C (even when we are taking the principal brach). So no, Wolfram's right here.

  • @MrBauchnabbel
    @MrBauchnabbel 3 года назад +55

    I think wolframalpha is right here. 1^x=2 has no solution but 1=2^(1/x) does. Grinding this down to fundamentals you see that (a^b)^c is not equal to a^(bc) for complex numbers, exactly because the change of branch of log you expertly portrayed in the video.
    Another instance that messes with this is my all time favourite:
    a = e^(log a) = e^((2\pi i / 2\pi i ) log a ) = (e ^ (2\pi i) ) ^ (log a / 2\pi i) = 1 ^ (whatever) = 1.

  • @hippityhoppity657
    @hippityhoppity657 3 года назад +908

    "ok so we'll just take a logarithm and set the base to 1"
    this triggers me

    • @InfiniteQuest86
      @InfiniteQuest86 3 года назад +40

      @Tessellating Tiger Lol then you can divide. He had to hide it lol.

    • @nanamacapagal8342
      @nanamacapagal8342 3 года назад +129

      Log base 1 is so cursed

    • @prashant2650
      @prashant2650 3 года назад +28

      log base one isn't defined in mathematics

    • @МаратМаранкян
      @МаратМаранкян 3 года назад

      @@prashant2650 in complex numbers too?

    • @BenedictMHolland
      @BenedictMHolland 3 года назад +16

      It is a rule that 1 to any power is 1. I assume this is true for all numbers but whatever tricks he is doing, you should always get a div by zero error.

  • @DepFromDiscord
    @DepFromDiscord 3 года назад +115

    “Yes, but not all the time”
    YOU’VE BROKEN MATH

  • @lykou1821
    @lykou1821 3 года назад +213

    The math police have issued a warrant for your arrest.

  • @danielyuan9862
    @danielyuan9862 3 года назад +95

    Okay if you solve for x in 1=2^(1/x) using wolfram alpha, you indeed get x=-i*ln(2)/(2pi*n), but as I have learned in math competitions, you should -always- usually plug it in to the original equation. And plugging x=-i*ln(2)/(2pi) as 1^x in wolfram alpha, you get 1. So x=-i*ln(2)/(2pi*n) are all extraneous solutions, which is why they are not solutions to the original equation 2^x=1.

    • @extraterrestrial46
      @extraterrestrial46 11 месяцев назад +2

      How exactly extraneous, wdym by that

    • @sashimidude3288
      @sashimidude3288 11 месяцев назад +6

      ​@extraterrestrial46 the original equation has a domain of all real x, and a certain range. The equation 1 = 2^(1/x) has a more restricted domain, and a different range. This changes the solutions, producing new solutions that do not work for eqn 1.

  • @slytan1506
    @slytan1506 3 года назад +1

    4:15 "I don't like to be on the bottom I like to be on the top"

  • @dr.kelpshake4573
    @dr.kelpshake4573 3 года назад +220

    2:59 I was gonna say 360 degrees like the child that I am. I can't wait to be an adult and say 2 pi!

    • @ojaskumar521
      @ojaskumar521 3 года назад +16

      Radians 4 adults 😎

    • @shakeztf
      @shakeztf 3 года назад +5

      2 7.18808272898
      funny factorial joke haha (or rather abuse gamma function for a factorial joke joke)

    • @jmhpt
      @jmhpt 3 года назад +5

      Or you can take it a step further and say tau!

    • @josefmuller86
      @josefmuller86 3 года назад +2

      Whaddaya mean 360°? 2pi? I only know 400 GRAD

    • @melonenlord2723
      @melonenlord2723 3 года назад

      @@josefmuller86 Every thing, that don't give you a round number, if it's a right angle, is stupid. ^^

  • @arandomelf3050
    @arandomelf3050 3 года назад +121

    As a random 13 year old, my mind imploded and exploded at the same time

    • @ManishGupta-hb4iu
      @ManishGupta-hb4iu 3 года назад +1

      ruclips.net/video/vUcNDYlBtoc/видео.html

    • @jondo7680
      @jondo7680 3 года назад +34

      So it cancels out and nothing happen to your mind.

    • @vibaj16
      @vibaj16 3 года назад +3

      @@jondo7680 nah, it just disintegrated in place

    • @jondo7680
      @jondo7680 3 года назад +3

      @@vibaj16 hey, I'm just someone trying to make a 13 years old feel dumb. Don't come with such high level stuff to me.

    • @jondo7680
      @jondo7680 3 года назад

      @Hans von Zettour Nobody knows

  • @musicisthefoodofthesoul
    @musicisthefoodofthesoul 3 года назад +208

    bprp: 1^x=2, x=?
    Wolframalpha: *By assuming x€R,...*

    • @angelmendez-rivera351
      @angelmendez-rivera351 3 года назад +76

      Wolfram Alpha does not assume x in R. Wolfram Alpha assumes the principal branch of exponentiation. In the principal branch, 1^x = 1 for all complex x. In order to get any other value, you have to assume the non-principal branch of Log(1).

    • @robdenteuling3270
      @robdenteuling3270 3 года назад +24

      @@angelmendez-rivera351 This man complexes

    • @abdulkabeer7313
      @abdulkabeer7313 3 года назад +7

      what is this principle and non principle branch?

    • @tupoiu
      @tupoiu 3 года назад +20

      @@abdulkabeer7313 Principle just means restricting our polar form to have an argument between 0 and 2pi.

    • @volxxe
      @volxxe 3 года назад +9

      @@tupoiu isn’t it from -pi to pi?

  • @danielc5313
    @danielc5313 Год назад +62

    Answer from google: Logarithm is not defined for base 1.

  • @JamesHesp
    @JamesHesp 2 года назад +56

    There are many things wrong with this video, but they serve as good indicators of why we need the concept of branches in complex analysis.
    Let us first see that some things are certainly not right:
    Suppose the reasoning by BPRP works, and that one can indeed write ln(1) = ln(e^(2pi*i*n)) = 2*pi*i*n, for any integer n. Then we run into the problem that ln(1) = ln(1^2) = 2ln(1). This immediately implies that ln(1) = 0, because that is the only solution to x = 2x. So either BPRP is wrong, or ln(1^2) = 2ln(1) is wrong. However, this same property of logarithms is used by BPRP himself when he writes ln(e^(2pi*n*i)) = (2pi*n*i)*ln(e), thus in any case BPRP's argument is not self-consistent. This property of logarithms should be familiar and we would certainly want this to be true. Let us now get to the heart of the problem.
    BPRP did not consider that in the case of inverting the complex exponential, you may not use all properties that we are used to when dealing with logarithms of real numbers. To 'invert' the complex exponential, you need to choose a specific branch, precisely to deal with problems like the one that we see in the video, namely that 1= e^2pi*i = e^4pi* i = e^6pi*i = e^(2pi*n*i) for any integer n. What does choosing a branch mean?
    Well from these equalities we see that there is no single inverse value to the complex expontential for the value 1: We need to choose one of the values 2*pi*n*i to get a step closer to defining something like an 'inverse' function to the complex exponential. Making such choices in order to always know which value to pick is (crudely speaking) what mathematicians call choosing a branch.
    The natural logarithm for complex numbers is an example where such a choice of branch has been made: The natural logarithm is defined for complex numbers by choosing the principal value branch, which restricts to the interval (-π, π]. This means that even though 1 = e^2pi*n*i for any integer n, when we use ln(e^(iθ)), we choose the value inside (-π, π] (even if θ is outside this interval!). In the case of ln(1) = ln(e^(2pi*n*i)) for any integer n, the natural logarithm then simply gives 0. This last point stresses that ln(e^(2pi*n*i)) = 0, thus the argument in the video does not work.
    Then one might be tempted to defend BPRP's argument by saying that he implicitly chose a different branch for the natural logarithm, precisely by asserting that ln(1) = 2pi*n*i for some integer n other than 0. However, even then one encounters the problem we discussed above: ln(1) = ln(1^2) = 2ln(1).
    This does not mean that one cannot take different branches for logarithms. Instead it means that when we do take a different branch, we cannot expect precisely the same rules to hold for our logarithm. In particular the rule for logarithms that log_a(b^c) = c*log_a(b) does not hold anymore if we choose a branch corresponding to ln(1) = 2pi*n*i for n ≠ 0. Of course this is a cherished property of logarithms, and motivates even more why mathematicians prefer to choose the principal value branch: It is the only branch in which this property holds.
    Thus in conclusion, BPRP's algebraic gymnastics to solve the equation 1^x = 2 is not correct, and upon further inspection Wolfram Alpha turns out to be exactly right: There is no solution to this equation. However there are some solutions to the equation 1 = 2^(1/x), which is NOT an equivalent equation. But my comment is long enough as is. If anyone is interested, I can elaborate more on this later.

    • @kevinruiz5659
      @kevinruiz5659 2 года назад +3

      Pretty interesting comment. I would like to see why 1 = 2^(1/x) its not an equivalent equation to 1^x=2. I'm guessing that it is because we also have to choose a branch of the function f(z)=z^(1/x) to apply on both sides?

    • @NowhereMan5691
      @NowhereMan5691 2 года назад

      interested

    • @aura-audio
      @aura-audio 2 года назад +4

      Thanks for bringing this up! In an engineering course I'm taking, the instructors were very up front about telling us to give our answers in terms of this interval. Now I'm starting to see why. Time to do some more research/learning.

    • @General12th
      @General12th 2 года назад +1

      Does this video do a disservice to the field?

    • @Lightn0x
      @Lightn0x Год назад +4

      It's much easier than that... the video is wrong from the first minute where they take log base 1 of both sides. You can't do that, that's equivalent to dividing by 0.

  • @edgardojaviercanu4740
    @edgardojaviercanu4740 3 года назад +138

    You have just extracted juice from a stone. It´s beautiful.

    • @PicaroPariah
      @PicaroPariah 3 года назад +4

      is this an idiom in your country?

    • @edgardojaviercanu4740
      @edgardojaviercanu4740 3 года назад +17

      @@PicaroPariah Not really. The expression in Spanish is: "sacar agua de las piedras".
      I preferred to use "juice" instead of "water". A failed poet, as you can see.

    • @porfiriodev
      @porfiriodev 3 года назад +5

      @@edgardojaviercanu4740 in portuguese is "tirar leite de pedra" which means extract milk from stones lol

    • @mihailmilev9909
      @mihailmilev9909 3 года назад +1

      @@yoonsooham3261 f

    • @mihailmilev9909
      @mihailmilev9909 3 года назад +1

      @@porfiriodev in Bulgarian it's water too

  • @akshitsingh5912
    @akshitsingh5912 3 года назад +27

    Teacher : 1 to the power anything is 1
    BPRP: Hold my M A R K E R

  • @vellagang678
    @vellagang678 3 года назад +373

    Wait a minute,
    Log base 1 is undefined
    Anyways,
    The pokemon in his hand is more important

    • @Kokurorokuko
      @Kokurorokuko 3 года назад +42

      So is division by 0, but he managed to get past it

    • @galgrunfeld9954
      @galgrunfeld9954 3 года назад +44

      @@Kokurorokuko L'hopital would be proud.

    • @amineelbahi2528
      @amineelbahi2528 3 года назад +28

      base 1 is undefined in R , he's working in C

    • @DanPolo3000
      @DanPolo3000 3 года назад +33

      base 1 is undefined in any Field, what he's doing is messing with the fact that log function on C is not a function by definition (one value of z leads to infinitely many values of log(z)), we have to use the principal value of log, the Log function, instead, which locks the n value to 0, and is bijective.

    • @DanPolo3000
      @DanPolo3000 3 года назад +4

      Literally doing that, if z1 = z2 then log(z1) = log(z2) in complex field, which is false (log in lowercase is not bijective!!!).

  • @robfrohwein2986
    @robfrohwein2986 3 года назад +1

    Great! Always something surprising.

  • @alkankondo89
    @alkankondo89 3 года назад +26

    The most EPIC beard in all of the RUclips Mathematics community! Also, LOL at that look-of-disappointment at 2:31! 😆

    • @blackpenredpen
      @blackpenredpen  3 года назад +7

      LOL thanks!

    • @ejb7969
      @ejb7969 3 года назад +3

      Love your username! The double-sharps in your logo caught my eye. Is that where the triple-sharp is in the Quasi-Faust?

    • @alkankondo89
      @alkankondo89 3 года назад +2

      @@ejb7969 Oh, wow! Thanks for noticing the reference. NOBODY has EVER noticed it before you! I extracted these notes from the 3rd movement of the Concerto for Solo Piano (Op.39, No.10). In addition to Quasi-Faust, there are 2 occurrences of a triple-sharp in this movement, after it modulates to the parallel major, F-sharp major. Again, thanks for noticing!! 👍😀

    • @ejb7969
      @ejb7969 3 года назад +2

      I didn't know that about the Concerto movement, and I've been over that score many times! (As a listener, not a player.)

    • @alkankondo89
      @alkankondo89 3 года назад +1

      @@ejb7969 Yeah, for the longest time, I also only knew about just the triple-sharp of Quasi-Faust. That’s the example that’s widely used in mentioning Alkan’s use of triple-sharps. I just happened to hear about the ones in the Concerto. They’re very easy to overlook in the torrent of notes in the score!

  • @conrad5342
    @conrad5342 3 года назад +39

    Thank you. This is one of the cases my Math Prof. warned me about. Does the imaginary unit really enable such relations or are the exponential / logarithmic laws more limited in the complex world than one might first time think?

    • @alexaisabird
      @alexaisabird 3 года назад +22

      the exponential function in the complex plane is not biejctive, and ln(z) is not the inverse of e^z

    • @frfrchopin
      @frfrchopin Год назад +2

      This is hard to accept since it's zero division of exponents

  • @violet_broregarde
    @violet_broregarde 3 года назад +21

    This answers a question I've had for a long time: does some math treat e^2 and e^(2+tau*i) differently? I learned something today. Thank you so much :D

    • @angelmendez-rivera351
      @angelmendez-rivera351 3 года назад +8

      e^2 = e^(2 + 2·π·i), but this does not imply 2 = 2 + 2·π·i. z |-> e^z is not injective if z is a complex number.

  • @twilightfox6948
    @twilightfox6948 3 года назад +13

    *blackandredpen: writes log1(2) to the board*
    Me: *wait, that's illegal!*

  • @gabrielfoos9393
    @gabrielfoos9393 2 года назад +5

    another way to solve this is 1=i^4n, n being an integer different than 0, you then have ln(i^4n)=4nln(i)=4nln(e^pi/2*i)=4n*pi/2*i, so ln(2)/ln(1)=ln(2)/4n*pi/2*i=ln(2)/2n*pi*i=-i*ln(2)/2n*pi, same result with a slightly different method

    • @Lightn0x
      @Lightn0x Год назад +1

      All good until "ln(2)/ln(1)". ln(1) = 0, so you are juat dividing by 0. Which is the same mistake in the video (just that in the video it's packaged differently). Wolfram alpha is correct, the equation has no solutions (including complex ones). The only way you get solutions is by doing something illegal (like dividing by 0).

    • @gabrielfoos9393
      @gabrielfoos9393 Год назад

      Yeah you are right but breaking the law is fun

    • @MagicGonads
      @MagicGonads Год назад +1

      @@gabrielfoos9393 ln(1) is not 0 for other branches of the logarithm in C, so it can be divided by for those, it's only the one that aligns with the real-valued logarithm (the principal logarithm) that has ln(1) = 0, it's usually the most convenient to use but *not the only one*

    • @gabrielfoos9393
      @gabrielfoos9393 Год назад

      Oh okay well I’m pretty new to complex logarithms, thanks for clarifying !

  • @helo3827
    @helo3827 3 года назад +46

    The first thing I noticed is he don't have glasses.

  • @ejb7969
    @ejb7969 3 года назад +12

    Question: Do you need the negative sign in the numerator? If n runs through all positive and negative integers, it's the same "solution set" with or without the negative sign ...
    ... isn't it ??
    PS - Your gentle emotional delivery here (moments of disappointment, exasperation, near-defeat) is a refreshing new contribution to the art of math videos!

    • @carultch
      @carultch Месяц назад

      It's a similar issue as when you rewrite the following diffEQ solution:
      y = e^(-x + C)
      as:
      y = C*e^(-x)
      The C came from a constant of integration that was completely arbitrary, and when we rewrite the final solution, the C is still an arbitrary constant. However, it is NOT the same arbitrary constant as you originally generated. Some professors insist you either assign subscripts or a tilde on top of one of them to tell them apart, or use a different letter entirely. If it were my choice, I'd accept a reuse of C, as long as write "Reassign C", or something else that means the same thing, to indicate that it isn't the same letter.
      Likewise, with this solution of:
      -i*ln(2)/(2*pi*n)
      The value of n is an arbitrary integer, so you could just as easily assign a different letter like m, and write it as:
      i*ln(2)/(2*pi*m)
      Heehee....pi m. Dr Peyam, this one is for you.

  • @ibrahimmassy2753
    @ibrahimmassy2753 3 года назад +4

    All depends of the branch of logarithm chosen because k^x=exp(x*"log"(k)) where you need specify the 2*pi magnitude interval of the imaginary part of function "log" how is defined; if it contains 0 there are no solutions. For example, the case of principal Log doesn't work because Log(1)=0; thus, for powers of principal branch 1^x is always 1

  • @docteuressciencemathematiq8461
    @docteuressciencemathematiq8461 Год назад +1

    In general, we can find the solution of
    x
    1 = P(n) where P(n) is a polynomial in R or C
    the solution is:
    -i(2 *Pi* k + Log ||(P(n)||)/2*Pi
    with ||(P(n)|| the modulus of P(n) and k a relative integer.
    it is the magic of complex numbers that allows this in particular the possibility of writing:
    1= exp(2*Pi*k)

  • @flowingafterglow629
    @flowingafterglow629 3 года назад +35

    I think this is probably my favorite problem you've done. It just shows how completely messed up things can get when you get to the complex plane, to the point where 1 raised to a power does not equal 1.
    Complex analysis is just bizarre.
    But in the end, this problem is so dang easy. You can get to things like
    -1^x = 10
    x = i ln 10/pi
    How crazy is that?

    • @chem7553
      @chem7553 Год назад +1

      Both beautiful and horrifying😆😆😆

  • @fetchfooldin3252
    @fetchfooldin3252 3 года назад +30

    😂😂😂 omg. I love the fact that you're searching for interesting equation to solve. That's amazing 👏🏻 keep going . This is your folower from Morocco ❤️

  • @W1ckedT0astr
    @W1ckedT0astr 3 года назад +9

    Math itself must've felt violated after the problem was solved

    • @viktorramstrom3744
      @viktorramstrom3744 3 года назад +5

      Wh-what are you doing, redpenblackpen-chan?

    • @Usuario459
      @Usuario459 3 года назад +2

      @@viktorramstrom3744 what are doing step brpr

  • @blackpenredpen
    @blackpenredpen  3 года назад +625

    2^x=-1 vs. (-1)^x=2 but in ONE minute
    ruclips.net/video/pBnS7K-uB-g/видео.html

    • @secavara
      @secavara 3 года назад +7

      Regarding this video, the two answers from wolfram alpha are consistent. b^z when b is real and positive and z is complex, is being taken in both equations as Exp[z Log[b]], where Log is a branch in which Log[b] is real. Hence, you get different answers in Wolfram depending on whether you ask Solve[1^x == 2, x] or Solve[2 \[Pi] I x m + 2 \[Pi] I n == Log[2], x]. Given the fact that you have the possibility to reach big audiences, you could make a bigger effort to present these topics in a more precise fashion, and use this topic to explore its nuances, and you are intentionally choosing not to do this.

    • @angelmendez-rivera351
      @angelmendez-rivera351 3 года назад +12

      @@secavara This is dishonest criticism, as the purpose of these videos are not to present the topic rigorously as understood by mathematicians. The purpose of these video are to showcase what happens when one is not careful, and to present topics heuristically, which is necessary before a student can begin to approach a complex topic with rigor. I have my disagreement with BPRP regarding how some subjects should be presented, but implicitly accusing him of being dishonest via your tone and wording when the criticism is not even applicable is itself dishonest and hypocritical.

    • @j.hawkins8779
      @j.hawkins8779 3 года назад +4

      i love how you hold a pokeball, because i love pokemon

    • @ManishGupta-hb4iu
      @ManishGupta-hb4iu 3 года назад

      ruclips.net/video/vUcNDYlBtoc/видео.html

    • @Kdd160
      @Kdd160 3 года назад +4

      @@secavara No! Bprp’s just having fun for the viewer’s entertainment!!

  • @Endrit719
    @Endrit719 Год назад +1

    if a guy holding a pokeball tries to prove something, he is trying to prove nothing

  • @Quidoute
    @Quidoute Год назад +2

    this man can bend reality

  • @yichen6313
    @yichen6313 3 года назад +9

    Cancelling log and exponent so casually gives me anxiety about messing up with branches....

  • @dissonanceparadiddle
    @dissonanceparadiddle 3 года назад +4

    Moving math into higher or adjacent dimensions is always a very neat thing to see. Things you think that are impossible become commonplace

    • @official-obama
      @official-obama 3 года назад +3

      no, jerry, you’re forgetting quaternions. there _is_ a solution for sin(e^(7x^2))=53x-25,000
      -elementary schools in the year 900000

  • @Simqer
    @Simqer Год назад +5

    This proves it, complex numbers were invented by mathematicians who were on some extremely good weed.

  • @axbs4863
    @axbs4863 3 года назад +2

    “But you know me I don’t like to be on the bottom I like to be on the top” bruh
    4:16

  • @Shikogo
    @Shikogo Год назад

    Dude your flicking motion to flip between the markers is so smooth.

  • @Compasseye
    @Compasseye 3 года назад +34

    I came here to see how many people undestand this, because boi i really weak in math. It took me hours to understand this, and open bunch of books about ln, log, and how they works. By the way i'm in 8th grade, and your vids helped me to understand lots more of how to calculate. So i thanked you for that 💙

    • @eekumbokum6770
      @eekumbokum6770 3 года назад +9

      I hate to do this but......r/imverysmart

    • @Safouan0
      @Safouan0 3 года назад +27

      @@eekumbokum6770 Not at all lmao. Lots of people are motivated to make positive changes in their lives...

    • @Lightn0x
      @Lightn0x Год назад +1

      The funniest thing is that the video is just wrong :). So if you really claim you understood it, then you didn't understand it enough :P. Hint: think about what it means to take log base 1.

    • @xinpingdonohoe3978
      @xinpingdonohoe3978 7 месяцев назад

      ​@@Lightn0x you don't have to take log base 1 though. Just express 1=e^(2πni) and take the natural log.

  • @W.2026
    @W.2026 Год назад +8

    Why tf is he holding a pokeball is he trying to get sued by nintendo

  • @aura-audio
    @aura-audio 2 года назад +25

    I love this! I'm taking an EE class right now which revolves around complex numbers, and your videos are super helpful/inspiring.

  • @apizcyril9479
    @apizcyril9479 3 года назад +2

    this guy can definitely explain to us how gojou satoru's power really worked mathematically

  • @Davide0033
    @Davide0033 11 месяцев назад

    i love how he explain in a way that i seem to understand, but then i realized i have no clue on what he's doing

  • @d4slaimless
    @d4slaimless 3 года назад +3

    Table at 6:03 it should be Ln, not Log I guess? Btw, like this you can get any number by replacing ln(2) with ln(k) where is the number (or it's power) that you want.

    • @wdyuyi
      @wdyuyi 5 месяцев назад

      actually "log" could have different meanings in each category we dealing with. Therefore, denote as "Ln" might be more clear👍

  • @nilsgoliasch244
    @nilsgoliasch244 3 года назад +4

    I have no idea why I'm watching this on a Saturday evening, but here I am

  • @slavsquatsuperstar
    @slavsquatsuperstar 3 года назад +3

    3:02 I’m pretty sure I heard “we are adults now, so we use 2 pi” xD

  • @Marco-os9yx
    @Marco-os9yx Год назад +2

    I came here because I was curious of how you would have solved the equation, to discover that behind it there was a story of a change of perspective. Great video, I had fun, even though I can't do all that math :)

  • @IsaacFoster..
    @IsaacFoster.. Год назад +1

    Thank God I still have my 12th grade knowledge to understand this randomly recommended video.

  • @antman7673
    @antman7673 3 года назад +7

    One of the first videos I was ahead of. Guess studying is paying off.

  • @hopewelltv8341
    @hopewelltv8341 3 года назад +152

    All I could see was the beard.

    • @betabenja
      @betabenja 3 года назад +6

      all I could hear was "stop looking at the beard! concentrate! concentrate!"

    • @riyadamin191
      @riyadamin191 3 года назад +1

      And his mic

    • @riyadamin191
      @riyadamin191 3 года назад

      This is also a clickbait 😂

  • @Electric_Bagpipes
    @Electric_Bagpipes 3 года назад +6

    When Wolfram alpha breaks you know your fkd.

  • @jirikoudelka7283
    @jirikoudelka7283 6 месяцев назад +1

    0:08 “lets introduce another imaginary unit j”

  • @sherkoza
    @sherkoza Год назад +1

    You can change ln(2) also to ln(2e^(i(0+2pi*m)))
    This way you can get more answers
    X=(ln(2)+2pi*m*i)/(2pi*n*i)

    • @duggydo
      @duggydo Год назад

      I think this might be why Wolfram won't give an answer. Too many possibilities.

  • @chzhao
    @chzhao Год назад +3

    A complex number raised to a complex power has multiple values. If we treat 1^x as such a multi-value expression, and the question is to find x so that 2 is one of values of 1^x, then x=-i*ln2/(2*pi) as stated in the video is a solution. Actually there are multiple solutions: x=-i*ln2/(2*pi*k) with k being any non-0 integer.

  • @nicknice7839
    @nicknice7839 3 года назад +3

    The pokemon in the pokeball in his hands probably learnt more maths than me

  • @itskarudo
    @itskarudo 3 года назад +21

    wait, that's illegal!

  • @ReasonMakes
    @ReasonMakes 11 месяцев назад +1

    Would be lovely to use tau instead of pi here

  • @william1729
    @william1729 Год назад +1

    4:17 “I don’t like to be on the bottom; I like to be on top” 😳

  • @bhabanidas1459
    @bhabanidas1459 3 года назад +4

    Starting the day with these kinda sums as a jee aspirant feels refreshing.

  • @ranjitsarkar3126
    @ranjitsarkar3126 3 года назад +4

    4:37
    My brain: starts melting

  • @taragnor
    @taragnor 3 года назад +10

    "They called me mad for trying to divide by zero! But I'll show them! I'll show them all! ahahahaha!"

  • @Yatornado
    @Yatornado Год назад +1

    1*1^(x - 1) = 2 | divide by 1
    1^(x - 1) = 2 | but 2 also equal to 1^x
    x - 1 = x
    -1 = 0 | and we can do it for any other integer not just -1, they are all equal to 0
    1^x = 2 is not the same as 1 = 2 ^ (1/x). Just like 1 = -1 is not the same as 1² = (-1)². Raisng equation to the power might change it's answer.

  • @Kommandant7
    @Kommandant7 3 года назад

    Fascinating question, hooked right away

  • @helloitsme7553
    @helloitsme7553 3 года назад +6

    Depend on which branch of 1^x you take

  • @tfdtfdtfd
    @tfdtfdtfd 3 года назад +8

    4:15.....why would he assume that WE know "HE" likes to be on the top rather at the bottom?

    • @MrAlRats
      @MrAlRats 3 года назад +2

      He considers all his viewers to be his rabid fans and expects us to have done the necessary enquiries so we are prepared if we ever meet him.

  • @denissudarev
    @denissudarev 3 года назад +39

    Is base 1 for logs exist?

    • @SupaGut2001
      @SupaGut2001 3 года назад +1

      I have the same questions...

    • @SupaGut2001
      @SupaGut2001 3 года назад

      But seems that exist in complex

    • @pendragon7600
      @pendragon7600 3 года назад +16

      No. Also, 1^x = 2 has no solutions.

    • @neon_trotsky
      @neon_trotsky 3 года назад +6

      When watching these videos I feel like I am fcking up whatever little maths I know

    • @hamsand2527
      @hamsand2527 3 года назад

      @@pendragon7600 then how did he do it using the laws of math?

  • @ryanrahuelvalentine2879
    @ryanrahuelvalentine2879 8 месяцев назад

    You are literally a hero!!!!

  • @shivx3295
    @shivx3295 Год назад +2

    Meanwhile me solving the derivatives on his back!

  • @stewartcopeland4950
    @stewartcopeland4950 3 года назад +7

    I will remember this: it is enough to take off your glasses to approach the problem from another perspective and solve it !

  • @mr_cod3
    @mr_cod3 3 года назад +6

    Hello there is a mistake from the beginning when u wrote X=log(2) because log(1)=0 so basically X is multiplied by zero

  • @shambobasu1579
    @shambobasu1579 3 года назад +57

    The title should be "10 ways to (not) write zero"

  • @BeyondKawaii
    @BeyondKawaii Год назад

    So thorough! Thanks a lot!

  • @Elliot-T
    @Elliot-T Год назад +1

    Wild complex number appeared

  • @xevira
    @xevira 3 года назад +6

    When the white hair comes in with the beard, BPRP will evolve into a super guru with mystical powers of calculus knowing how to write the Lambert W function in its elementary form.

  • @nipunkumar1175
    @nipunkumar1175 3 года назад +4

    *I don't know if 1^x will be 2 or not,but I surely like your Pokemon mic*

  • @amytg777
    @amytg777 3 года назад +5

    Sir, I’m going to major in mathematics at uni, and your videos both make me realize how terrifying that is but also somehow reassure me.

  • @Grasuggan22
    @Grasuggan22 3 года назад

    very good calm explanatory teacher

  • @uelssom
    @uelssom 3 года назад +1

    the solution is always " add peyam" if you want to solve maths even better if you add 2 peyam

  • @H336-p1v
    @H336-p1v 3 года назад +41

    How about "x tetration i = 2" :0

  • @yoursole6817
    @yoursole6817 3 года назад +7

    You should make a video on x^x=x^2
    Obviously 1 and 2 are the only real solutions but I did this with some code I wrote, it would be interesting to see how the actual math works. Also what about complex solutions

    • @blackpenredpen
      @blackpenredpen  3 года назад +6

      Love your quick explanation! You would have to rule out 0 since 0^0 is not defined. Also 0^0 isn’t 0^2.

    • @MathElite
      @MathElite 3 года назад +3

      @@blackpenredpen Hey thanks for the feedback! I appreciate it so much. I edited the title and description
      I'm trying the whole math youtuber thing, I like it so far (inspired by you and others)

    • @esajpsasipes2822
      @esajpsasipes2822 Год назад

      @@blackpenredpen i think it is defined for algebra purposes, but even with that it's not a solution as 0^0 =/= 0^2 => 1 =/= 0

  • @va-y-dit7843
    @va-y-dit7843 3 года назад +27

    100 LIMITS, i need that !!!

    • @va-y-dit7843
      @va-y-dit7843 3 года назад +2

      i got a eaxam in 4 days, i believe in you

    • @harshvardhanpandey8057
      @harshvardhanpandey8057 3 года назад +4

      What about 100 limits without L'H

    • @integralboi2900
      @integralboi2900 3 года назад +7

      With epsilon-delta!

    • @sakshitandel8572
      @sakshitandel8572 3 года назад

      @@harshvardhanpandey8057 jee aspirant ???

    • @b.b.a.2886
      @b.b.a.2886 3 года назад

      @@sakshitandel8572 he means l'hospital rule. It's like a cheat code for limits

  • @uamdbro
    @uamdbro 2 года назад +1

    I like how people just automatically assume that literally any equation must have some solution in the complex plane lol

  • @osleff
    @osleff 3 года назад

    What a great video, the ending really makes it all the more satisfying.