Worked example: arc length | Applications of definite integrals | AP Calculus BC | Khan Academy

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  • Опубліковано 4 лис 2024

КОМЕНТАРІ • 51

  • @aidansmith6906
    @aidansmith6906 3 роки тому +7

    My professor's teaching online for the semester so she can just reuse all her old videos from the last 3 semesters. This 15 minute-series explains everything way better than her 30-minute video could ever hope to

    • @jimj2683
      @jimj2683 Рік тому

      So many professors are getting paid fat $100k+ salaries while essentially not working at all.

  • @DonOtto15
    @DonOtto15 2 роки тому +1

    I like how you write your radicals, I might have to adopt that

  • @pepegpala
    @pepegpala 7 років тому +27

    some times i hate math,i come here,back to being a lover.

  • @leonidesubackup7501
    @leonidesubackup7501 4 роки тому +3

    this is perfect for before test review!!

    • @mysticaxolotl8215
      @mysticaxolotl8215 7 місяців тому

      I finally started passing my exams after I remembered Kahn Academy existed lol

  • @SciHeartJourney
    @SciHeartJourney 2 роки тому +1

    Thank you very much!

  • @HimanshuSoni_Axelerate
    @HimanshuSoni_Axelerate 10 років тому +5

    Please someone tell me which application is used by Sal, besides using Bamboo tablet? Not the recording app, but the app that Sal uses to write on? Is it Smoothdraw?

  • @neelmodi5791
    @neelmodi5791 10 років тому +3

    Thank you so much I understand how to do it now!

    • @rickandelon9374
      @rickandelon9374 7 років тому +1

      Wolfram alpha thanks for your help in doing my homeworks!!

  • @johntindell9591
    @johntindell9591 6 років тому +1

    thank you very much

  • @bolis925
    @bolis925 8 років тому +16

    why do we change the boundaries of the definite integral? is it because we used u-sub?

    • @justin60222
      @justin60222 8 років тому +18

      Yes, the integral was with respect to x and you changed the integral with respect to u so you must change your limits.

    • @RobbyBoy167
      @RobbyBoy167 7 років тому +6

      not necessarily a must. It's just an alternative way of doing it.

    • @ThatGuy09890
      @ThatGuy09890 6 років тому +2

      FIFA Lords & Legends True. If you didn't change the limits, you could have still gotten the problem right by substitutions the original expression you had for u back into the equation, but that would be longer and can lead to tiny errors. Changing the limits is the best way to do it.

    • @jillian2414
      @jillian2414 6 років тому

      Yea

    • @williamkoleszar3301
      @williamkoleszar3301 6 років тому +1

      if you don't change bounds to be with respect to u, you must un-sub u so your expression in it terms of x. You can't mix u and x.

  • @jillian2414
    @jillian2414 6 років тому +1

    Thank you so much. 😘

  • @qualquan
    @qualquan 2 роки тому

    Pretty good but hesitates to call ds a tangent since he thinks like others that a tangent is a point with no length. Used the term "loosey goosey" when deriving the ds formula (ha ha).
    Yet they integrate tangents to get length of a curve.

  • @surendrakverma555
    @surendrakverma555 7 місяців тому

    Good

  • @renzoandre5286
    @renzoandre5286 8 років тому

    What conceptual proof video from before is he talking about? I must see it.

  • @lisky4u
    @lisky4u 10 років тому +1

    Isn't there suppose to be a 2Pie in front of the integral? Or is that only for finding the surface area of the arc?

    • @excelery3125
      @excelery3125 2 роки тому

      yeah its for the surface area only i think

  • @linkster5564
    @linkster5564 7 років тому

    at 2:15 cant we just leave it as √(1+((3/2)x^(1/2))^2)? that way the square root cancels out the square so we would just have to integrate 1+(3/2)x^(1/2)?

    • @Mrwiseguy101690
      @Mrwiseguy101690 6 років тому +4

      You can't distribute exponents over a polynomial. sqrt(1+x^2) does not equal sqrt(1) + sqrt(x^2).

    • @HeyKevinYT
      @HeyKevinYT 4 роки тому +3

      Cease before the math police comes to arrest you

    • @adibzinnurine7917
      @adibzinnurine7917 3 роки тому +1

      Sqrt(a+b) and sqrt(a)+sqrt(b) are not the same thing. Go study well enough before watching these videos.

  • @ricjadelacruz2808
    @ricjadelacruz2808 5 років тому +3

    Isn't it 8 when we multiply (32/9)(9/4)?

  • @AVSbeats
    @AVSbeats 2 роки тому +1

    Who pauses the video to work on it 👁 👁

  • @anthonycarroll7222
    @anthonycarroll7222 6 років тому +2

    when i did the u sub for the bounds i got u = 8 not 9

  • @jahidurjaman9024
    @jahidurjaman9024 5 років тому

    If f(X)=x^2 then find the length of arc

  • @ainfatini2821
    @ainfatini2821 3 роки тому

    is there a unit for the lenght?

    • @omniyambot9876
      @omniyambot9876 3 роки тому +2

      It's just unit. We're im coordinate plane and we use x and y distance.

  • @lexinaut
    @lexinaut 10 років тому

    The Ghosts of Departed Quantities (that is the differentials) would approve, I think. Very nice if infinitesimally quirky presentation.

  • @adibzinnurine7917
    @adibzinnurine7917 3 роки тому

    4:27 Me be like: What? Dealing with me?

  • @ptyptypty3
    @ptyptypty3 2 роки тому

    so, I can throw away my abacus now? :)

  • @alex-dn9to
    @alex-dn9to 4 роки тому

    what i wanna duuu ( derivative of d with respect to u joke)

  • @Dudepghbeats
    @Dudepghbeats 6 років тому +7

    My teacher sucks

  • @lisky4u
    @lisky4u 10 років тому

    Isn't there suppose to be a 2Pie in front of the integral? Or is that only for finding the surface area of the arc?