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  1. #1
    Nidhogg
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    Calculus help?

    i need help with calculus math... i am having trouble with chainrule combined with other rules... need major help

  2. #2
    Relic Horn
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    Re: Calculus help?

    I see no problem for us to solve, so you must want links?
    Try poking around here until someone shows up with a better one. Or just give us a problem to solve/explain while we complain about being used as a homework hotline.

  3. #3
    Conejita's Jolly
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    Re: Calculus help?

    So wuts your q, niggra? Is it rules in general, or a specific problem you need help on? If it's the former, then just visit Paul's online Calculus, if it's the latter, just post the q.

    Edit: Damn was late with the reply :O

  4. #4
    Nidhogg
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    Re: Calculus help?

    Y = 2^sinpix

    The answer won't help me, can anyone show me steps plz?

  5. #5
    Conejita's Jolly
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    Re: Calculus help?

    Why are you using "y"? That implies implicit differentiation, is it?? I don't think so ;x

    Anyways:
    d/dx = (sin(pix))^2 = 2(Sin(pix)^1 (subtract one from the power 2, chain rule).
    Next differentiate the base: 2(Sin(pix)^1(Cos(pix)),
    then the derivative of the inner function:2(Sin(pix)^1(Cos(pix)(pi). So the answer is: 2pi(Sin(pix))(Cos(pix) = 0 I just woke up, so dunno if I got it right >_>

    *Sin (pi) = 0, so when you multiply you get zeroth.

  6. #6
    Final Fantasy XI Music Devotee

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    Re: Calculus help?

    F(x) = 2^sin(pi*x)

    f(x) = 2^x
    g(x) = sin(x)
    h(x) = pi*x

    so:

    F(x) = f(g(h(x)))

    Let's derivate, apply the chain rule:

    F'(x) = f'(g(h(x))) * (g(h(x)))'

    Now, derivate g(h(x)), applying the chain rule again:

    (g(h(x)))' = g'(h(x)) * h'(x)

    Put it all together:

    F'(x) = f'(g(h(x))) * g'(h(x)) * h'(x)

    Now let's get f'(x), g'(x), h'(x):

    f'(x) = (2^x) * ln(2)
    g'(x) = cos(x)
    h'(x) = pi

    Do the substitution:

    F'(x) = (2^(sin(pi*x))) * ln(2) * cos(pi*x) * pi

    I hope this was clear enough, when you get used to it you can skip many of the steps.

  7. #7
    Relic Horn
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    Re: Calculus help?

    It might be easier to think about if you call the parametric functions f(t), g(t) and h(t), to keep yourself from thinking they're all the real x.

  8. #8
    Nidhogg
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    Re: Calculus help?

    Just want to say I'm envious of all your math skillz. I aced all of my calculus classes in college but never used them since graduation so I barely remember any of it.

  9. #9
    Ridill
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    Re: Calculus help?

    I used to love math, I took college algebra and now I'm in statistics... Don't think I'll be taking anymore math.

  10. #10
    Demosthenes11
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    Re: Calculus help?

    can do it a much easier way than substitution

    y = 2^sin(pi*x)
    ln|y|=sin(pi*x)*ln(2) Take derivative here
    1/y*dy=cos(pi*x)*pi*ln(2)*dx
    dy/dx=cos(pi*x)*pi*ln(2)*y=cos(pi*x)*pi*ln(2)*2^sin(p i*x)

  11. #11
    C A P S UNLEASH THE FURY
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    Re: Calculus help?

    Quote Originally Posted by Demosthenes11
    can do it a much easier way than substitution

    y = 2^sin(pi*x)
    ln|y|=sin(pi*x)*ln(2) Take derivative here
    1/y*dy=cos(pi*x)*pi*ln(2)*dx
    dy/dx=cos(pi*x)*pi*ln(2)*y=cos(pi*x)*pi*ln(2)*2^sin(p i*x)
    the guy needs help on the chain rule, i don't think using the dx rules for natural logs is going to make him any less confused at this point >_>

    I would like to note that simply reading all of this instead of seeing it with the actual symbols makes it more difficult to understand, you should seek help IRL instead of online maybe >.>

  12. #12
    Conejita's Jolly
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    Re: Calculus help?

    Oh shi, I thought it was (Sin(pix))^2 >__________________________________> Use parenthesis mofro :O

  13. #13
    Saint Daahan Von Quitter the 1st
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    Re: Calculus help?

    I can't do problems like that without my Calculus notebook

  14. #14
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    Re: Calculus help?

    Quote Originally Posted by Xajii
    the guy needs help on the chain rule, i don't think using the dx rules for natural logs is going to make him any less confused at this point >_>

    I would like to note that simply reading all of this instead of seeing it with the actual symbols makes it more difficult to understand, you should seek help IRL instead of online maybe >.>
    Ditto. Let's ask for a LaTeX mod!

  15. #15
    My Little Ixion
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    Re: Calculus help?

    OMG.. yallaremeltinmybrainwithurevylcalculusthreadkthxdi e!

  16. #16
    BG Medical's Student of Medicine
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    Re: Calculus help?

    Calculus.

    It says you + me = us.

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