_-substitution: multiplying by a constant | AP Calculus AB | Khan Academy

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  • Опубликовано: 5 ноя 2024

Комментарии • 53

  • @guitarstuffs1236
    @guitarstuffs1236 4 года назад +5

    There's an easier way to think of u-sub...
    You can just solve and substitute for dx instead of trying to make it match du...
    When you have your du/dx expression, just get dx by itself and then substitute into the integral.

  • @lexinaut
    @lexinaut 10 лет назад +8

    Very helpful for me, him, her, and ESPECIALLY . . . U!

  • @namechane1758
    @namechane1758 9 лет назад +7

    You saved me, Larson Calculus texts and online resources are unimpressive mockery of Khan Academy. How can something free be more informative than an $180 loose-leaf text book?

  • @neillopez5146
    @neillopez5146 8 лет назад +9

    Dude thanks I have a math quiz next period.Pls pray for me

  • @zhijin0201
    @zhijin0201 6 лет назад

    Khan Academy saved my day.....Great explanation

  • @DanTeyKSA
    @DanTeyKSA 11 лет назад +7

    no need to distribute 1/7 to c because in the end it will be = new C

  • @daedra40
    @daedra40 9 лет назад +3

    ease the monotony? Sal's voice is to me the cure to the monotony of life itself (wherever applicable) xD

  • @keotshepilemandona9882
    @keotshepilemandona9882 6 лет назад +2

    with khan i find it easier for me to start the topic and then do questions with the organic chemistry tutor..........

  • @tommichalsen3847
    @tommichalsen3847 11 лет назад

    Because with he is integrating with respect to u. Remember, the u is a substitute for the original expression, so for the integral to be valid, we must integrate with respect to that variable. Just to toying around with u-substitution yourself to get a feel for it, because otherwise, u-subs won't make sense at all. U-subs are mathemagical so they can't be conurued unless you WILL it. (If you're a bard, you need Charisma. Remember to put points into concentration or else the u-sub will interrup.

  • @gijsoerlemans7738
    @gijsoerlemans7738 9 лет назад +6

    I UNDERSTAND THE UNIVERSE!!!

  • @KatiePancione
    @KatiePancione 6 лет назад

    THIS HELPED ME SOO MUCH!!!!!!!!!!!!!!!!!! Big fan of this!

  • @MaryamPirzada
    @MaryamPirzada 8 лет назад +7

    i laughed harder than i should've when you said "hairy integral".

  • @sbriscoe13
    @sbriscoe13 10 лет назад +2

    nice example, nice lesson. Thank you

  • @thesamman18
    @thesamman18 10 лет назад +21

    The Bob Ross of math

    • @goodstuff7375
      @goodstuff7375 3 года назад

      So what are you up to these days??

    • @thebatsbury8053
      @thebatsbury8053 2 года назад

      @@goodstuff7375 what are YOU up to these days?

  • @edgartoro8459
    @edgartoro8459 6 лет назад

    Thank you very much.

  • @AdamLongint0x191f2
    @AdamLongint0x191f2 6 лет назад

    Good video!!! thanks

  • @Xdrakemanx
    @Xdrakemanx 12 лет назад

    sal u droppin knowledge aginn

  • @Lukeriddoch
    @Lukeriddoch 12 лет назад

    haha u subs are definitely an art, luckily once u practice al the different types they are not bad unless u get some crazy question lol.

  • @blackfrancis33
    @blackfrancis33 4 года назад +1

    Why does du disappear when you take the antiderivative?

    • @thebatsbury8053
      @thebatsbury8053 2 года назад

      Integrate dx. It becomes 1. Anything multiplied by 1 remains same

  • @qualquan
    @qualquan 2 года назад

    good

  • @zhijin0201
    @zhijin0201 6 лет назад

    How u determine the u and du/dx?

  • @MikeKain95
    @MikeKain95 12 лет назад

    U subs are arcane black magic

  • @YahiaDesigner
    @YahiaDesigner 6 лет назад

    what if you have a higher order polynomial inside of the square root?

  • @arrowhead1195
    @arrowhead1195 11 лет назад

    Why did you stop including du? It was as if you forgot about it. Whats the point of having it?

  • @A_Dopamine_Molecule
    @A_Dopamine_Molecule 12 лет назад +1

    Just for laughs, I tried to do that in my head in 10 seconds and skip to the end to check the answer. How in god's name did I get it right if I'm 2 days sleep deprived and almost failed calculus 2...

  • @ImperiaGin
    @ImperiaGin 8 лет назад +3

    how does it become 1/7 times 7?

    • @JooJingleTHISISLEGIT
      @JooJingleTHISISLEGIT 7 лет назад +5

      he needed a times 7, the only way to do that without changing the value is to also divide by 7.
      because x/x = 1
      and a x 1 = a

  • @MrJustinCr3dible
    @MrJustinCr3dible 11 лет назад

    it goes away once you take the integral (anti derivative) of it

  • @sizetomtas
    @sizetomtas 10 лет назад +1

    It feels weird. Am I really aloud to write the problem like that, My first thoughts were to go like this
    (7(x+9/7)^(1/2))
    and then put it out like this
    ((du*u)^(1/2))
    Can some one explain why I'm wrong ?

    • @floppyflippster
      @floppyflippster 10 лет назад +1

      that is exactly what i though. i don't understand where the 1/7 comes from

    • @PoweredMinecart
      @PoweredMinecart 8 лет назад

      +sizetomtas In your first line, the 7 is not included in the ^1/2 power. 7 is the du, so in the second line, the du should not be included in the ^1/2 power.

  • @coldbrewandbear
    @coldbrewandbear 6 лет назад

    Why the du which is 7*dx just be ignored at the end?

  • @SDkoolKidd
    @SDkoolKidd 9 лет назад

    So does the du go always go away

  • @katandmart
    @katandmart 10 лет назад

    Sound a lot like Kevin Smith!... smaths

  • @Mihirskates
    @Mihirskates 9 лет назад +1

    I laugh so hard when sal says hairy integral

    • @69bitboy
      @69bitboy 9 лет назад

      +Mihirskates me too lmao

  • @EduardoRohdeEras
    @EduardoRohdeEras 7 лет назад

    those "dx" constantly remind me Nikon....

  • @TheBruiseBox
    @TheBruiseBox 11 лет назад

    did he say "a hairy looking integral"? 0.o i would understand SCARY... but hairy?

  • @cristianreyes8288
    @cristianreyes8288 6 лет назад

    why does the du just go away

  • @tommichalsen3847
    @tommichalsen3847 11 лет назад

    And a lot of typos. Grammat nazis beware, retribution will be swift. Consider thyself warned!

  • @w2010rcdas
    @w2010rcdas 12 лет назад

    first club

  • @ecdctechmma
    @ecdctechmma 8 лет назад +1

    your wrong bro its 14/3