The answer is correct but the way I did it was wrong. I have to L'Hopital's but how? Reddit calculus

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  • Опубликовано: 30 сен 2024
  • How do we evaluate the limit of x^tan(x) as x goes to 0+? This is a must-know calculus 1 limit that requires L'Hopital's Rule. Make sure we don't just write 0^0 approaches 1 since 0^0 is a limit indeterminate form.
    0^0 approaches 0: • finally 0^0 approaches...
    0^0 approaches e: • a 0^0 limit that appro...
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Комментарии • 75

  • @bprpcalculusbasics
    @bprpcalculusbasics  4 дня назад +2

    0^0->0 ruclips.net/video/BThNFV9f-L0/видео.htmlsi=_PuuOGSjJZqDyLtF

  • @saigow349
    @saigow349 3 дня назад +5

    Hey, I know that you don't prefer the ILATE method. But, can you please teach me ILATE? My teachers aren't really accepting the DI method and saying that it is "out of syllabus"😭

    • @dannyyeung8237
      @dannyyeung8237 13 часов назад

      Can I use Taylor series with tan(x) to solve for the answer?

    • @pneujai
      @pneujai 10 часов назад

      ILATE and DI have no contradictions, you can use ILATE with DI, and DI is just a tabular representation, if you write the steps out, DI is acceptable for every single calculus course that allows by parts

  • @xinpingdonohoe3978
    @xinpingdonohoe3978 4 дня назад +45

    This is why people saying 0⁰=1 is an issue. It's situational. A limit of the form 3² is not indeterminate, it's 9. A limit of the form 6-4 is not indeterminate, it's 2. A limit of the form 0⁰ is indeterminate, and you must respect that. Sometimes it will be 1, but not all the time.

    • @MikehMike01
      @MikehMike01 4 дня назад +7

      No one says that the limit of 0^0 is 1
      The algebraic operation 0^0 is an unrelated discussion

    • @psymar
      @psymar 3 дня назад +3

      ​@@MikehMike01plenty of people say 0⁰ is 1 without even bringing limits into it. these people are wrong but it's a common belief among non-mathematicians

    • @MuffinsAPlenty
      @MuffinsAPlenty 3 дня назад +1

      No matter what you do, people will make mistakes. One just has to teach what indeterminate limiting forms are, and expect students to actually learn it. Again, no matter how good a teacher is, some students will still make mistakes.

    • @MuffinsAPlenty
      @MuffinsAPlenty 3 дня назад +3

      @@psymar "plenty of people say 0⁰ is 1 without even bringing limits into it. these people are wrong but it's a common belief among non-mathematicians"
      It's also a pretty common belief among mathematicians. In situations where exponentiation is _discrete_ (where exponents _mean_ repeated multiplication), 0^0 = 1 is correct. This does not mean that the _limiting form_ 0^0 should be evaluated as one. We have to remember how limits don't have to match the value of a function at the point in question.

    • @MikehMike01
      @MikehMike01 3 дня назад +2

      @@psymar yes, 0^0 (not a limit) should be defined as 1. That has nothing to do with the limit of 0^0, which is indeterminate.

  • @HiddenKey_210
    @HiddenKey_210 4 дня назад +9

    Math is my love language

  • @REIDAE
    @REIDAE День назад +3

    In reality, if you want to know the limit of any function approaching 0, you just have to sub in something like 0.000000001 and you'll be able to easily deduce the answer.

    • @Hextor26
      @Hextor26 День назад +4

      Found the engineer

    • @sowndolphin5386
      @sowndolphin5386 День назад

      alr

    • @REIDAE
      @REIDAE День назад

      ​@@Hextor26 I do actually have a degree in engineering lol

    • @pavlopanasiuk7297
      @pavlopanasiuk7297 20 часов назад

      It is meaningful, but situational. Many functions in physics and engineering have their "natural scale", and you have to know it before plugging a number. Your number must be small RELATIVE to that scale; and I'm not even mentioning sometimes this scale doesn't exist (along with the limit). So unfortunately its not foolproof

    • @dannyyeung8237
      @dannyyeung8237 13 часов назад

      Can I use Taylor series with tan(x)

  • @bra1nwave172
    @bra1nwave172 3 дня назад +1

    If you don't split the limit into a product of limits you would have -sin^2(x)/x -> -sin(2x) through L'Hopitals Rule. Finally, substituting x = 0 leads to the same limit of 0 in the exponent and thus 1 for the limit of the original expression as x appproaches 0 from the right.

    • @dannyyeung8237
      @dannyyeung8237 13 часов назад

      Can I use Taylor series with tan(x) to solve for the answer?

  • @spicca4601
    @spicca4601 4 дня назад +3

    What condition is required for lim(x->something)f(x)=f(lim(x->something))?

    • @orilevi7
      @orilevi7 4 дня назад +10

      It requires f to be a continuous function. It's derived from the limit of composition of functions

    • @Grecks75
      @Grecks75 2 дня назад

      Continuity. It's essentially the definition of continuity.

    • @hach1koko
      @hach1koko 23 часа назад

      Continuity at that something, specifically

  • @xl000
    @xl000 4 дня назад +4

    lavalier mic goes on your collar
    this would free your left hand

    • @General12th
      @General12th 3 дня назад +5

      It's intentional.

    • @RecreationallyCynical
      @RecreationallyCynical 3 дня назад +4

      BPRP used to use one of those larger, spherical, desk microphones and would just hold it in his left hand as he was doing the video. He switched to a smaller mic, but wanted to keep holding something in the videos, so he held a pokéball plush. I don't know what happened to the pokéball, but he's still keeping the tradition alive by holding the mic.

    • @bprpcalculusbasics
      @bprpcalculusbasics  2 дня назад +2

      Don’t worry. Nothing happened to the pokeball. : )

  • @alexanderpanov2326
    @alexanderpanov2326 4 дня назад +2

    Thanks a lot from Nuremberg!

  • @General12th
    @General12th 3 дня назад +1

    I taught students about the cotangent table and graph today!

  • @thethinkinlad
    @thethinkinlad 3 дня назад

    really want a tee like that for myself but they won't ship to my region //:

  • @shaqshock
    @shaqshock 4 дня назад +2

    How to get the t shirt????in Canada that is

    • @bprpcalculusbasics
      @bprpcalculusbasics  4 дня назад +2

      Hi there, can you check the Amazon link in the description and let me know if it works for Canada? Thank you!

    • @shaqshock
      @shaqshock 4 дня назад +1

      It says it doesn't deliver to Canada...

    • @bprpcalculusbasics
      @bprpcalculusbasics  4 дня назад +1

      @@shaqshock that’s a bummer. I will have to look into that to see what I can do.

    • @shaqshock
      @shaqshock 4 дня назад +1

      @@bprpcalculusbasics please do thx.... Otherwise I will have to find a place in states.... 😢😢😢

    • @bprpcalculusbasics
      @bprpcalculusbasics  3 дня назад

      How about this on Spring? blackpenredpen.creator-spring.com/listing/cat-and-indeterminate-forms?product=2

  • @dannyyeung8237
    @dannyyeung8237 13 часов назад

    Can I use Taylor series with tan(x)

    • @pneujai
      @pneujai 10 часов назад

      it makes this question way harder

    • @pneujai
      @pneujai 10 часов назад

      unless you only take the first term of the expansion, noting that tanx~x

  • @IrrelevantGuy
    @IrrelevantGuy 3 дня назад

    😂😂😂😂❤😡😡

  • @chasmosaurus3
    @chasmosaurus3 4 дня назад +3

    A small shortcut lim_{x-> 0^+} tan(x) = x

    • @dannyyeung8237
      @dannyyeung8237 13 часов назад

      Can I use Taylor series with tan(x) to solve for the answer?

    • @pneujai
      @pneujai 9 часов назад

      you should either write tanx~x or lim tanx/x=1, because x is undefined on the right side

  • @unturnedd
    @unturnedd 3 дня назад

    can we just say that in the limit to 0 tanx becomes x?

    • @dannyyeung8237
      @dannyyeung8237 13 часов назад

      Can I use Taylor series with tan(x) to solve for the answer?

  • @JP-lz3vk
    @JP-lz3vk 4 дня назад

    Like it.

  • @DjVortex-w
    @DjVortex-w 3 дня назад

    Actually it can be proven that if you have an analytic function to the power of another analytic function, both approaching 0, then the result always approaches 1. (You can even find a published paper about this.) So technically the original method is mathematically valid.
    All the counter-examples, where the limit does not approach 1, have one or both functions non-analytic at that 0.

    • @MuffinsAPlenty
      @MuffinsAPlenty 3 дня назад

      "Actually it can be proven that if you have an analytic function to the power of another analytic function, both approaching 0, then the result always approaches 1."
      Yes, but that theorem probably wasn't covered in this calculus class.

    • @ThomasTheThermonuclearBomb
      @ThomasTheThermonuclearBomb 3 дня назад

      The original answer didn't say anything about analytic functions, AND it says (at least in the thumbnail that the limit is equal to 0^0 and then is therefore equal to 1, which is blatantly wrong

    • @DjVortex-w
      @DjVortex-w 3 дня назад

      @@ThomasTheThermonuclearBomb
      Well, you don't need to always name the theorem when you use one. Do you always explicitly write "by Pythagoras' theorem" when you use it, for example?

    • @ThomasTheThermonuclearBomb
      @ThomasTheThermonuclearBomb 3 дня назад

      @@DjVortex-w I didn't say name the theorem. I said to mention the analytic functions. I'd write something like "This is the limit as x approaches 0 of an analytic function to the power of another analytic function, so the limit equals 0" but less wordy. And you can't say 0^0=1, period.

    • @dannyyeung8237
      @dannyyeung8237 13 часов назад

      Can I use Taylor series with tan(x) to solve for the answer?

  • @superjugy
    @superjugy 4 дня назад +3

    How did we pass from sinx/x to 1?

    • @ingiford175
      @ingiford175 4 дня назад +2

      Standard Calc proof in doing derivatives of sin and cos you have to use sin(x)/x is 1 as X approaches 0. If you proved the trig functions using inverses, then you can bypass the sin(x)/x part of the proof.

    • @marie-juhanna1281
      @marie-juhanna1281 4 дня назад

      Can`t we just do it using L' Hospitals rule again? Because, if we evaluate for x=0, we have a 0/0 situation. And if we take the derivative top and bottom, we just get cos(x)/1 and cos(0)=1.

    • @StarDusk17
      @StarDusk17 4 дня назад

      @@marie-juhanna1281 In order to know the derivative of sin(x) you need to use the definition of the derivative, and to evaluate that limit you need to evaluate the limit of sin(x)/x. So for this limit, we can't use L'hopital's rule without knowing the derivative of sin(x), and we can't know the derivative of sin(x) without first evaluating the limit. It's circular reasoning

    • @ingiford175
      @ingiford175 3 дня назад

      @@marie-juhanna1281 Reason you do not use L'H is because you need sin(x)/x limit as part of the (most used) proof of of the derivative of sin(x). The logic is circular.

    • @robertveith6383
      @robertveith6383 3 дня назад

      You wrote that wrong. You need grouping symbols: sin(x)/x.

  • @msolec2000
    @msolec2000 3 дня назад

    Yes, lim sinx/x = 1, but lim sinx/n is different. The n cancels out and you're left with six.