Derivative of ln (x) using the definition of derivative

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  • Опубликовано: 1 окт 2024
  • I used the definition of the derivative to show that d/dx ln(x) =1/x

Комментарии • 36

  • @WolfgangFeist
    @WolfgangFeist 9 месяцев назад +8

    Second last step: you need to use "continuity" of ln(x). (Because:with still finite x/h the term in the ln is not yet 'e').
    BTW: I love the way you are presenting this explaining every step (in a calm and friendly way). Most teachers try to do it in a hurry. That is the main reason, why some students get annoyed with math.

  • @SpiroGirah
    @SpiroGirah 3 года назад +10

    I never thought of this! Good job!

  • @boguslawszostak1784
    @boguslawszostak1784 5 месяцев назад +2

    If you define ln(x) as the integral from 1 to x of 1/u du, you have no problems computing its derivative. It is equal to 1/x by definition of the function.

  • @Th3OneWhoWaits
    @Th3OneWhoWaits 7 месяцев назад +1

    8:58 as h goes to 0, "n" or x/h goes to infinity. Thus, lim as h goes to 0 = lim n goes to infinity.

  • @sldw3221
    @sldw3221 Год назад +2

    Hello sir, i'm seeing that we always using definition of e with limit while proving all of these formulas but is it actually possible for you to explain or prove how or why limit n->infinity (1+1/n)^n is equal to euler's number? Did you record a video about this or would you talk about that in another video if it's possible? Thanks

  • @barthennin6088
    @barthennin6088 Год назад +3

    Beautiful! 1st time seeing this truly from first principles!

  • @averagestudent5222
    @averagestudent5222 9 месяцев назад +2

    This guy turns math into magic

  • @Harrykesh630
    @Harrykesh630 4 месяца назад

    just a suggestion 😁
    It might be too late to point out but, you could have started by first proving that ln(x) is indeed differentiable by Left and Right hand derivative then go on to find it.

  • @sandraboateng5435
    @sandraboateng5435 Год назад +2

    😍😍👌👌✊✊👍👍

  • @januszek1760
    @januszek1760 8 месяцев назад +1

    (1 + 1/(x/h))^(x/h) is not equal e

    • @Artemis1855-k4w
      @Artemis1855-k4w 18 дней назад +1

      as h approaches 0, x over h approaches infinity, if you replace x/h with a variable it's more legible

  • @temporarychannel9759
    @temporarychannel9759 Год назад +1

    the enthusiasm made this really enjoyable to watch, great job

  • @manoharkanade7383
    @manoharkanade7383 Год назад +2

    Very good explanation ❤

  • @holyshit922
    @holyshit922 Год назад +1

    He missed step when he used fact that ln is continuous

  • @elai3147
    @elai3147 2 года назад +2

    5:31, as h goes to zero wouldn't x/h go to either positive infinity or negative infinity?

    • @xavierwainwright8799
      @xavierwainwright8799 2 года назад

      This works because lim x-> -inf (1+1/x)^x is also equal to e, but I don't know any proofs without using the derivative of ln(x) (this would be circular reasoning).

    • @cblpu5575
      @cblpu5575 Год назад +1

      Recall that the domain of ln (x) is **positive real numbers only** hence x/h is a positive real number x divided by a quantity h tending to zero

  • @alexdcruz3682
    @alexdcruz3682 6 месяцев назад

    Love your videos

  • @wilsonhicke5598
    @wilsonhicke5598 3 месяца назад

    Love this

  • @salamalmudarris5032
    @salamalmudarris5032 Год назад +1

    But n is integer while x/h is real number?

  • @EliiiAkotha
    @EliiiAkotha 4 месяца назад

    Great job

  • @nellwackwitz
    @nellwackwitz 3 года назад +1

    You are AWESOME!!

  • @ecSruthipriyaMahesh
    @ecSruthipriyaMahesh 5 месяцев назад

    I really like your classes, thank you for your hard work! 😃

  • @nichodimuszishiritinashe8329
    @nichodimuszishiritinashe8329 2 года назад +1

    You are the best

  • @surendrakverma555
    @surendrakverma555 6 месяцев назад

    Very good. Thanks 👍

  • @wira2562
    @wira2562 8 месяцев назад

    It's very useful to understand the inderivatived integral of dx/x sir!

  • @EternalScienceAndTech
    @EternalScienceAndTech 9 месяцев назад

    You are a great man

  • @katiatzo
    @katiatzo 11 месяцев назад

    BRAVO

  • @joelmwape4239
    @joelmwape4239 2 года назад +1

    You are the best

    • @PrimeNewtons
      @PrimeNewtons  2 года назад +1

      Thank you for your kind words.

  • @hassanejturay2994
    @hassanejturay2994 Год назад

    Awesome

  • @samwelkariuki3114
    @samwelkariuki3114 2 года назад +2

    Always the best teacher.....what about 1/x

  • @licksorestockpile1190
    @licksorestockpile1190 Год назад

    Solid videos!