Induction Inequality Proof Example 5: 2^n ≥ n²

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  • Опубликовано: 22 окт 2024

Комментарии • 168

  • @IffyProjects
    @IffyProjects 8 лет назад +164

    but i don't see how, when seeing a problem like this for the first time, you'd know to replace n^(2) by 2n + 1. I don't see how you would know to do that.

    • @wm78965kidtips
      @wm78965kidtips 8 лет назад +15

      +IffyProjects exactly...i was wondering the same thing

    • @sirswig
      @sirswig 8 лет назад +21

      +IffyProjects I agree. I mean, logically, it makes sense, but I automatically assume I CANNOT deviate from the problem due to getting it wrong in school. In real life, yes I could maybe make the assumption, but I wouldn't want to assume anything outside the direction of the problem when quizzes or tests come into play. I'd like an answer as well. "HOW did you know to do this step?"

    • @renecianiesie9662
      @renecianiesie9662 8 лет назад +3

      +IffyProjects ...I agree with you!!

    • @fabse64
      @fabse64 8 лет назад +6

      +IffyProjects The only reason he did it the way he did was to make the proof look neater. You can absolutely start with the original inequality without replacing anything, and you'll eventually complete the proof. As OP pointed out in the first couple of minutes of the video, you'll arrive at a problem and have to take a step back solving the problem first.

    • @walidzein1
      @walidzein1 7 лет назад +3

      it takes practice

  • @halimjoshua2277
    @halimjoshua2277 10 лет назад +39

    hi! its very helpful, but I'm wondering how can you come up with the 2n+1 in the first place?

    • @TechToppers
      @TechToppers 4 года назад +12

      In induction, you check first what you have to proof.
      Like 2^{k+1}>(k+1)²=k²+2k+1
      Now to proof
      2^k+2^k>k²+2k+1
      Reduces down(by hypothesis)
      2^k>2k+1
      If you proof this, you're done!
      It has been 5 years since you posted. I hope so you have grown and could find it by yourself!

    • @FSHnegativ
      @FSHnegativ 4 года назад

      @@TechToppers I have been working on this problem for the past hour or two and you explained it so so well in one small comment. Thanks a ton just had my Eureka moment have a nice day

    • @TechToppers
      @TechToppers 4 года назад +2

      @@FSHnegativ
      Thanks a lot. But please remember, that the I wrote was just for intuition. Backtracking in mathematics is generally hard. You have to be very sure that your assumptions are correct.
      In which grade you are?

    • @FSHnegativ
      @FSHnegativ 4 года назад +1

      @@TechToppers im currently in the first semester of uni majoring in data science. Haven't had induction proofs in high school so I'm doing my best learning it as fast as possible. I actually just got done with the whole proof (n^2

    • @reubenmanzo2054
      @reubenmanzo2054 3 года назад

      @@TechToppers How does the reduction work? Because you're halving one side and square-rooting the other.

  • @Twannnn01
    @Twannnn01 4 года назад +1

    If anybody was wondering why 2^n > n^2 becomes 2^n * 2 > n^2 * 2 is because in order to get 2^n+1 you need to multiply 2^n by 2 (hence 2^n * 2). Since it's an inequality n^2 becomes n^2 * 2.

  • @yifpye8895
    @yifpye8895 3 года назад +3

    8:36 I don’t get how you can say 7 is greater than/equal to 0...

  • @shyamal245
    @shyamal245 2 месяца назад +1

    this proofs are left me speechless😭

  • @Wolfun1t
    @Wolfun1t 7 лет назад

    Why not use a chain for the first one?
    For example:
    assume: 2n + 1

  • @MaddSTATIC
    @MaddSTATIC 10 лет назад +7

    great video, it really helped me out! :)
    The only problem i have is this: why do you assume that 2^n is greater than or equal to 2n+1?

  • @beru58
    @beru58 6 лет назад

    You can go like a heat seaking missile right to the end. No need for ”expeditions” here and there.
    1) Show that it is true for a smallest value of p. Bla bla
    2) Assume the statement to be true for p.
    3) Show that under the above assumption it is also true for p + 1. That is
    (p + 1)^2 LE 2^(p + 1) expand on both sides p^2 + 2p + 1 LE 2 * 2^p that is p^2 + 2p + 1 LE 2^p + 2^p
    Make use of our assumption under 2). That is, it now suffices to show that
    2p + 1 LE 2^p.
    But 2p + 1 LE p^2 since after we subtract 2p and add 1 we get
    2 LE p^2 - 2p +1 LE (p - 1)^2,
    which is true for p = 4, 5, 6,…
    And again by our assumption under 2)
    2p + 1 LE p^2 LE 2^p
    Q. e. d.
    Comment:
    What we are as a whole to prove, and our assumption is like a balance leaning over to the right. We make use of our assumption and take away on both sides. The balance must not flip over to the other side! That is what suffices to prove. (And to do that we use our assumption once again.) Hope you see what I mean with a balance. The kind Mdm Justitia uses.

    • @beru58
      @beru58 6 лет назад

      Sorry. Typofix. Should have been
      But 2p + 1 LE p^2 since after we subtract 2p and add 1 we get 2 LE p^2 - 2p +1 = (p - 1)^2, which is true for p = 4, 5, 6,…

  • @johanfredrikberthlingherbe4419
    @johanfredrikberthlingherbe4419 10 лет назад +1

    Nice video! One question though. Isn't the whole first part a bit unnecessary if you could simply prove that (2^k-(2k+1)) >= 0 for k>=4, which it is. Or am I not allowed to just insert 4 like that?

  • @mpcc2022
    @mpcc2022 8 лет назад +16

    How does one know the correlary piece they need to prove before hand?

  • @alexanderbaron2378
    @alexanderbaron2378 7 лет назад +2

    But how is 7 greater or equal to 0? How can we make that assumption, when 7 would never equal 0?

    • @giuliobranchetti5584
      @giuliobranchetti5584 5 лет назад

      7 has to be greater (which is the case) OR equal to 0.
      Otherwise a>=b would be true only if a=b=0.

  • @charlenec.6166
    @charlenec.6166 9 лет назад

    Thank you so much! But I don't understand why you can't you do it directly.
    ie.
    assume true for n=k
    so 2^k is greater than k^2
    then rtp: n= k+1
    so 2^(k+1) is greater than (k+1)^2
    LHS= 2 x 2^k then sub in the assumed stuff and becomes 2x2k^2
    RHS=k^2+(2k+1)
    LHS is greater than RHS because k^2 is greater than 2k+1 for k>4
    why can't you do it this way?

    • @zhaoningding7599
      @zhaoningding7599 8 лет назад

      +Charlene Chau 2x2k^2 IN lANE 7 shouLD BE 2xk^2

  • @tethyn
    @tethyn Год назад

    Would you consider the first proof the lemma that you need for the current proof or proof in consideration? Good job:

  • @Zzznmop
    @Zzznmop 6 лет назад +7

    In my opinion, the flowchart at the beginning is more important to those who want to teach the subject whereas for students it may add another layer of difficulty since these videos are primarily watched by people who need reinforcement on the title/topic.

  • @kobilica999
    @kobilica999 10 лет назад +11

    You solved exactly same thing I got for homework, heh :D
    Now I understand it completely.

  • @namelessnormie
    @namelessnormie 2 года назад +1

    BTW, RTP means required to prove

  • @robertj4424
    @robertj4424 5 лет назад

    Assume 2^k > k^2 for k > 4. 2^(k+1) = 2(2^k) = 2k^2 > 2k^2 = (k+1)^2 + k^2-2x-1 > (k+1)^2, since k^-2k-1 = (k-1)^2-2 > 0 for k>4

  • @barbie7913
    @barbie7913 10 лет назад

    Your explanation was very helpful. I have had this question before but could not just figure out the induction step . I did understand what you did in both the first case and second but I have a small question. I understand that 2 to the power k+1 =2 to the power n times 2 but I don not seem understand how and why you had to write 2 to the power n+ 2 to the power n. May you please help me on that. Thank you..

    • @barbie7913
      @barbie7913 10 лет назад

      ***** Hello,you can find that part at 13:00 to about 13:10 . And it is 2 to the power k + 2 to the power k. Sorry ,I used n because I am always using n in my induction step too.Thank you.

  • @aku7598
    @aku7598 3 года назад

    I do it this way, hope it's correct.
    2.2^k>=2.k^2
    2^(k+1)>=(k+1)^2
    To prove 2.k^>=(k+1)^2
    2.k^2>=k^2+2k+1
    k^2-2k-1>=o.......(1)
    True if k>2.4...

  • @asimami3061
    @asimami3061 2 года назад

    Can we do it by putting the equation on one side and zero on another side for every inequality question??????

  • @ospreytalon8318
    @ospreytalon8318 3 года назад

    I would just use 2^(k+1)>=2k^2 from the assumption, then it's a simple matter of proving 2k^2>=(k+1)^2 for each k>=4

  • @kunalvshah
    @kunalvshah 6 лет назад +1

    @ 8:39, it should be > 0 not > or = 0 correct? if something is > or = 7, it is > 0 not > or = 0 right?

  • @khalidbaraka4073
    @khalidbaraka4073 8 лет назад +1

    why did you start with 2^(n)>and equal to 2n+1

  • @Ikhtesad
    @Ikhtesad 8 лет назад

    Hi, I don't know if you still do videos or not. I found your
    explanations to be very simple and clear and wondered if you could show
    me how to do the following proofs:
    (1) let lcm(a,b) = l so l=pa and l=qb
    Prove that gcd(p,q) = 1
    (2) if gcd(a,b) = 1 prove that gcd(a+b, a-b) is either 1 or 2.
    (3) Prove that if a | (bc) and gcd(a,b)=1 then a|c
    (4) If d=gcd(a,b) and f is any other common divisor of a and b, prove that f | d
    Any help with any of them is appreciated. If you don't do this anymore no problem. Thanks for all your videos.

    • @AryamanMaithani
      @AryamanMaithani 7 лет назад

      Hey, I don't know if this would still be helpful but:
      Question 1: I'm going to do a proof by contradiction:
      p = l/a
      q = l/b ... (Given)
      Let's assume that gcd(p, q) ≠ 1 ... *(1)*
      Therefore, l/a and l/b have a common factor, say F
      Since, it's a factor, F is a positive integer ≠ 1
      => l/a = mF; l/b = nF; where n and m are positive integers ≠ 1
      => am = l/F; bn = l/F
      => l/F is a common multiple of both 'a' and 'b' (Since, m and n are integers > 1)
      Since F>1, this implies that l > l/F
      => lcm(a, b) = l/F ≠ l
      But, we know that lcm(a, b) = l
      Therefore, our assumption *(1)* was wrong.
      Therefore, gcd(p, q) = 1

    • @TechToppers
      @TechToppers 4 года назад +2

      Everything is standard Number Theory plug in some numbers and try to understand it's behaviour and then formalize.
      It has been 4 years but still😂

    • @TechToppers
      @TechToppers 4 года назад

      I can give you intuition if you want...

  • @AmanKumar-ut5gh
    @AmanKumar-ut5gh 3 года назад +1

    Sir, why m√a^n = a^n/m please explain

  • @memofahood4543
    @memofahood4543 10 лет назад

    Thank you soo much for ur explanation,but I have a question why do assume that 2^n is greater or equal to 2n+1. Thank you

    • @hellojellyy4108
      @hellojellyy4108 8 лет назад

      +Eddie Woo how do you know that you'll be needing that proof later on ?

    • @brasco7659
      @brasco7659 7 лет назад

      Stian Sapiens I think u were not paying attention to the first 3 min of the video,. where he says he will do step 2 first and then step 1 and finally step 3.

  • @victorserras
    @victorserras 6 лет назад

    The one thing I don't get about induction: why just assume something is true for n, then show it's true for n+1, if what you wanted to prove in the first place is that it's true for n?

    • @TechToppers
      @TechToppers 4 года назад

      Good question I know the answer. Should I tell?

  • @kalunlee5854
    @kalunlee5854 7 лет назад

    2*2^(k)-(2k+1)>=k^2-2k+1-2=(k-1)^2-2 ,since k>=4,(k-1)^2>=9 -->k^2-2k-1>=9-2=7>=0
    so i don't think we need to prove n^2>=2n+1

  • @alexandretaranoff714
    @alexandretaranoff714 8 лет назад

    actually you didnt have to demonstrate past 6:04 when you write consider as we multiplied by 2 which is a positive number which won't change the inequality right ?

  • @renecianiesie9662
    @renecianiesie9662 8 лет назад

    Ek wil graag weet hoekom is 2 tot die mag ' n' groter en gelykaan ( 2n +1)? En by die einde van die bewys hoekom is k groter en gelykaan 4??(induction inequality example 6).

  • @dania4485
    @dania4485 8 лет назад +1

    Thank You soo much for this, but could you also prove n

  • @RAKESHCHAUHAN-jm7bt
    @RAKESHCHAUHAN-jm7bt 5 лет назад +4

    2.2power k
    How convert 2 power k + 2 power z
    Tell me

  • @snenhlanhlabongeka4541
    @snenhlanhlabongeka4541 6 лет назад +1

    Thank you this video was very helpful. ..but am a little bit confused. ...how come 2^k+1 =2^k+2^k. ...help

    • @hadishaikh7532
      @hadishaikh7532 5 лет назад

      2^k+1 is equal to 2^k×2(Indices rule that is bases same so add powers)...then 2^k×2 means 2^k is written two times that is 2^k+2^k.

  • @snethembamsomi9390
    @snethembamsomi9390 8 лет назад +7

    I don't get how you have two 2^k in 2.2^k. I'm confused

    • @haloshiroe
      @haloshiroe 3 года назад

      really late but that's not the case, 2^(k+1) is just 2(2^k) he wrote it as 2.2^k which is really 2*2^k

    • @snethembamsomi9390
      @snethembamsomi9390 3 года назад +1

      @@haloshiroe that's like from 4 years ago 😭 but thank you nonetheless. Your video helped a great deal🌟

    • @sbongamthethwa8506
      @sbongamthethwa8506 Месяц назад

      @@snethembamsomi9390 here i am now currently confused😭

  • @perroisdog8519
    @perroisdog8519 8 лет назад +6

    Hi Eddie, I find your videos very helpful, I kind of wonder the same thing like some other viewers here, can you explain a little more in detail when you swap n^2 by 2n+1, and how I can get to this step in general, for instance if I have to prove 2^(n-1)bigger and equal to n^2. Thanks very much!

    • @pizzarickk333
      @pizzarickk333 Год назад

      Ik it's been 6 years but here's how I think about it;
      If A < B, we can edit this inequality so that it still becoles true.
      If A is less then B, then A is less than any number that's greater than B
      So if we swap B by a greater number, the RHS would become larger, hence keep being larger than A.
      It's all about making the hand side larger or smaller (by swapping for bigger or smaller numbers) so that the inequality remains true.

  • @anzatzi
    @anzatzi 7 лет назад

    is it possible to start at step 2 if you had never worked this problem? Not likely

  • @jameschen2308
    @jameschen2308 4 года назад

    You are an excellent teacher, and that would be an understatement.

  • @Trifers
    @Trifers 9 лет назад

    Hi eddie, i'm currently working on an assignment whereby, my assignment ask for to prove by induction that 2^n > n^2 for n>=5.
    is it possible for me to prove it ur way as ur question is quite similar?

    • @TechToppers
      @TechToppers 4 года назад

      That is same actually.
      n≥5 means all n greater than 5 including 5.
      n>4 means same...
      I know you have done your assignment but I thought to explain 😂
      Btw, you could have replaced the given condition by condition in the video as they both are same...
      That's a 5 years ago...

  • @ke_tebza
    @ke_tebza 6 лет назад

    In 3:38, you said that LHS is greater than or equal to RHS when you have only shown that LHS is greater than RHS, for n = 4. You have not necessarily convinced me about equality of the two sides.

  • @lenasp122
    @lenasp122 10 лет назад

    Hi Eddie! Your video helped my alot! But I still have one question.
    Why did you change the letter n to k (n=k) and didn't continue using the letter n?
    Thank you !

  • @游宜宸-b8j
    @游宜宸-b8j 6 лет назад

    I finally understand why you have proved that 2^n≥2n+1 is true at first, thank you so much!!
    Now I have another question, which is familiar with this one, that is: to prove that 3^n>n^3,{n=4,5,6...}
    Thank you.

  • @desmondacheampong4873
    @desmondacheampong4873 7 лет назад +2

    please solve 2n less than n! for, n greater or equal to 4

  • @LOLxUnique
    @LOLxUnique 11 лет назад +1

    does this solution work for 2^n > n^2 ?? > not >=

  • @mmmmSmegma
    @mmmmSmegma 9 лет назад +2

    I'm already getting the feeling that this video is gonna be directly responsible for a love affair I' going to have with mathematics for the next year or so.

    • @shady490
      @shady490 3 года назад +3

      im curious, how did your love affair go?

  • @kythconney7412
    @kythconney7412 7 лет назад

    How do you prove this using minimum counterexample?

  • @johnhurley8918
    @johnhurley8918 10 лет назад

    Wait a minute! This is the same guy in the video about parity bits that I watched! Man, this guy is all everywhere.

  • @laux927
    @laux927 9 лет назад +1

    Thanks! Best explanation I've found. Finally got it!

  • @RAKESHCHAUHAN-jm7bt
    @RAKESHCHAUHAN-jm7bt 5 лет назад

    2 question I don't understand after consider. How plus 2 power k

  • @Snapeserverussnape
    @Snapeserverussnape 4 года назад

    I clicked the video without looking at the channel but immediately recognized Eddie Woo the moment he said the word "here."

  • @rgqwerty63
    @rgqwerty63 9 лет назад

    Majorly overcomplicated.
    When you had 2^(k+1)-(k+1)^2 you could simply rearrange to 2(2^k-k^2) + (k-1)^2 - 2 which is certainly positive for k>=4

  • @lolanifenring2692
    @lolanifenring2692 6 лет назад

    Shouldn't it be "n = { 4,5,6,... }," not "{ n = 4,5,6,... }"?

  • @alexmelendezrolon872
    @alexmelendezrolon872 8 лет назад +1

    Ok anyone watching this video: before you go and comment about not understanding something, take the time to carefully watch the ENTIRE thing. It will all makes sense :D

    • @TechToppers
      @TechToppers 4 года назад

      But it's complicated for no reason...

  • @akshatchheda1102
    @akshatchheda1102 6 лет назад

    Can you do a video for 4^n > n^4 ??

  • @anitaojwani
    @anitaojwani 5 лет назад

    I am from India my ? How can you return as n square is equal to 2n+1 .but why

    • @danieldorsz1047
      @danieldorsz1047 4 года назад

      This is the question Anita ! Can anyone answer ?

    • @anitaojwani
      @anitaojwani 4 года назад +1

      @@danieldorsz1047 yes dear

    • @danieldorsz1047
      @danieldorsz1047 4 года назад

      @@anitaojwani so I was hoping you have found the answer because your comment was posted 6 months ago haha is anyone else interested ? Give some answers people !

  • @OnslaughWins
    @OnslaughWins 8 лет назад +6

    why is it 2k+3

    • @pop0potato
      @pop0potato 7 лет назад +4

      Because when he plugged in k + 1 into 2k + 1, he got 2(k + 1) + 1 which becomes 2k + 2 + 1 which is 2k + 3!

    • @corb2347
      @corb2347 7 лет назад

      Cheers bro

    • @pulanemolotsi6998
      @pulanemolotsi6998 7 лет назад

      thank you so much for this

    • @snenhlanhlabongeka4541
      @snenhlanhlabongeka4541 6 лет назад

      it because when you simplfy 2 (k+1)+1 it will give you 2k+3

  • @lopangwaynemoalosi3131
    @lopangwaynemoalosi3131 9 лет назад

    Sir why did you replace 2^k by K^2 ?

    • @debevc11
      @debevc11 9 лет назад

      +Lopang Wayne Moalosi because 2^k is greater than k^2 by assumption, you replace 2^k by k^2 in the next row and replace sing = with greater than :D 13:27 check again :)

    • @lopangwaynemoalosi3131
      @lopangwaynemoalosi3131 9 лет назад

      Thanks a lot...i see!
      It now makes sense.

    • @debevc11
      @debevc11 9 лет назад

      +Lopang Wayne Moalosi np :D

  • @theabeatriz
    @theabeatriz 5 лет назад +4

    thanks for this video! now i am even more confused haahah

  • @kevinfarhat9978
    @kevinfarhat9978 7 лет назад

    why is 2^k>2k+1

  • @Kojoakomeaopare
    @Kojoakomeaopare 9 месяцев назад

    I don't get it

  • @evelynwallace25
    @evelynwallace25 8 лет назад

    7:54 - Where did the 2k - 1 come from? I thought it was 2k + 1.

    • @NyteRazor
      @NyteRazor 8 лет назад +2

      +Angela Fawn Leach continued from the previous steps... 2(2k+1)-2k-3 ..multiply 2 to get rid of parens making 4k+2-2k-3 then combine like terms... 4k-2k+2-3 making 2k-1

  • @kng4822
    @kng4822 8 лет назад

    Is induction the only way to solve this kind of problem...
    This is genuinely not an easy thing to grasp.

    • @TechToppers
      @TechToppers 4 года назад

      You could use some calculus I suppose...

  • @mschindee4997
    @mschindee4997 3 года назад

    The best explanation I watched so far

  • @suppertoon3927
    @suppertoon3927 7 лет назад

    n^2 = 2n+1 ????

  • @MatteoBlooner
    @MatteoBlooner 8 лет назад

    2^3 is smaller than 3^2

  • @SathvickSatish
    @SathvickSatish 6 лет назад

    What level of algebra is this?

    • @SathvickSatish
      @SathvickSatish 6 лет назад

      and what grade will I learn this? These proofs are so interesting

    • @TechToppers
      @TechToppers 4 года назад

      Basic😂
      Really

  • @lynk.9479
    @lynk.9479 10 лет назад

    for any positive integer n, 6n - 1 is divisible by 5.

  • @faiazhossain9066
    @faiazhossain9066 5 лет назад +1

    Dude thank you. I needed this explanation ❤️

  • @dnxtheone1252
    @dnxtheone1252 9 лет назад

    You are my savior.

  • @eilertulio8137
    @eilertulio8137 6 лет назад

    @ 8:46
    7 is >= 0
    why can you make 2^(k+1) - (2k+3) >=0
    does it mean that it can also be =1? since it's >=0?
    but it should also be >=7 right?
    I can somehow understand the whole video but I want to fully grasp the concepts. I think there's something wrong somewhere in my understanding. Enlighten me please.

    • @eilertulio8137
      @eilertulio8137 6 лет назад

      How can it affect, or does the EXACT number at the LHS really affect the whole equation? or just the category it belongs to matters (negative, positive,etc)?

  • @silenna77
    @silenna77 3 года назад

    Demostró que 2^n > 2n+1.
    Pero debía demostrar 2^n > n².
    😬

  • @franklin6103
    @franklin6103 7 лет назад +2

    you are honestly the best math teacher

  • @abood7aj
    @abood7aj 10 лет назад +15

    how 2.2^k = 2^k+ 2^k ?????

    • @МаксимМарков-з7с
      @МаксимМарков-з7с 8 лет назад

      is this a standard way to depict multiplication?

    • @remavas5470
      @remavas5470 8 лет назад +1

      +Максим Марков i thought/think the standard way is *

    • @remavas5470
      @remavas5470 8 лет назад

      +Remavas ...on a computer :)

    • @mpcc2022
      @mpcc2022 8 лет назад

      Максим Марков 2x2 is the same as 2+2. I think it only works with 2.

    • @abood7aj
      @abood7aj 8 лет назад +1

      +Joshua L thanks but now its 2016 hahahha

  • @tshiovhekhuthadzo129
    @tshiovhekhuthadzo129 10 лет назад

    Thank you for this wonderful video. I learnt a lot:D

  • @annajadun1994
    @annajadun1994 3 года назад +1

    2021

  • @normantakavarasha2936
    @normantakavarasha2936 7 лет назад

    thank you very much .that was helpful

  • @eccesignumrex4482
    @eccesignumrex4482 10 лет назад

    Let me get another beer ...

  • @エイサップロッキー-g2q
    @エイサップロッキー-g2q 5 лет назад

    微分して増減調べればいいのでは?

  • @mlungisijadu224
    @mlungisijadu224 5 лет назад

    More videos plz it's interesting

  • @TheEglene
    @TheEglene 7 лет назад

    I love mathematics!

  • @lopangwaynemoalosi3131
    @lopangwaynemoalosi3131 9 лет назад

    i got it......Thanks a lot Sir.......

  • @gaimz1855
    @gaimz1855 5 лет назад

    Thanks

  • @fathemaher5178
    @fathemaher5178 6 лет назад

    thank you from palistine

  • @danakapoostinsky8337
    @danakapoostinsky8337 7 лет назад

    Thank you!!

  • @nadhirarizky
    @nadhirarizky 9 лет назад +1

    Thank you :D

  • @vansf3433
    @vansf3433 3 года назад

    That problem is too easy
    Prove this one
    (2n)! > n^n

  • @bismeetsingh352
    @bismeetsingh352 7 лет назад +21

    How can n^2 be replaced by 2n+1? You didn't explain the first step and this whole video is senseless

    • @Georgelegeng
      @Georgelegeng 7 лет назад

      i have the same question

    • @adamcforsythe
      @adamcforsythe 6 лет назад +3

      It does if you watch the whole video.

    • @ukgaming1084
      @ukgaming1084 6 лет назад +2

      If you're attempting this proof by yourself, you would have started with what he did towards the end of the video. And then realised you had to prove the lhs was greater than or equal to 2n+1

    • @TechToppers
      @TechToppers 4 года назад

      First, plug in some numbers if you don't get the Algebra. That's the best way!
      Then you will understand in no time

  • @akshayan1340
    @akshayan1340 9 лет назад

    Wow. That was great

  • @thespacesmoothie
    @thespacesmoothie 8 лет назад

    Thank you, I understand now :D

  • @thenameisbrandoongle
    @thenameisbrandoongle 10 лет назад

    Good work, buddy.

  • @DiegoMartinez-zh1cf
    @DiegoMartinez-zh1cf 8 лет назад

    thanks !!!

  • @fernandoortiz1849
    @fernandoortiz1849 10 лет назад

    thank you thank you thank you thank you thank you thank you thank you thank you thank you thank you thank you thank you reeaaaaaalllllyyyyyyyy muuuuuuch!!!!!!

    • @fernandoortiz1849
      @fernandoortiz1849 10 лет назад

      jaja , really i was the only one who brings the algebra homework right, and my teacher give an extra point on my exam thanks to you :D

  • @davidomoyajowo4284
    @davidomoyajowo4284 10 лет назад

    o ga o.. oponu oshi

  • @talentmaritinyu2095
    @talentmaritinyu2095 7 лет назад

    thanks boss

  • @ntouches
    @ntouches 7 лет назад

    problem is ur first teacher

  • @dodu8105
    @dodu8105 6 лет назад

    Thwis syde wud be bigga

  • @wyattguthrie823
    @wyattguthrie823 2 года назад

    I love you

  • @nonononononono3883
    @nonononononono3883 3 года назад

    wait wha?

  • @sangesherpa4832
    @sangesherpa4832 4 года назад

    Not helpful at all man. Even made more confused