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Math Help - chain rule

  1. #1
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    chain rule

    Find the derivative of the function. y = a9 + (cos(x))9

    It keeps saying its wrong... heres what i did:

    sum rule,

    derivative of a^9 + derivative of (cos(x))9

    9a^8 + ..........

    outside function = x^9
    derivative of outside function= 9x^8
    inside function= cos(x)
    derivative of inside function= -sin(x)


    ......... 9(cos[x])^8 * -sin(x)

    9a^8 + (9(cos[x])^8 * -sin(x))






    Its asking for y'(x)=
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  2. #2
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    Quote Originally Posted by Evan.Kimia View Post
    Find the derivative of the function. y = a9 + (cos(x))9

    It keeps saying its wrong... heres what i did:

    sum rule,

    derivative of a^9 + derivative of (cos(x))9

    9a^8 + ..........

    outside function = x^9
    derivative of outside function= 9x^8
    inside function= cos(x)
    derivative of inside function= -sin(x)


    ......... 9(cos[x])^8 * -sin(x)

    9a^8 + (9(cos[x])^8 * -sin(x))






    Its asking for y'(x)=
    if y is a function of x, then a^9 is probably a constant ... the derivative of a constant is 0
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  3. #3
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    your right, thanks.
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