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Math Help - Derivative

  1. #1
    Junior Member
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    Derivative

    I'm doing some Calculus homework on linear approximations and differentials right now, and I'm stuck trying to find the differential of this function:

    f(x)= x^2 sin2x

    My book says that the answer is dy= 2x(xcos2x + sin2x)dx, but I cannot reproduce that answer. I think that this derivative may have something to do with the double angle formulas for sin2x and cos2x, but I don't know where to begin. Will someone please show my how to find this derivative?


    Thanks,
    Zach
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  2. #2
    Math Engineering Student
    Krizalid's Avatar
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    Product rule yields:

    2x sin2x + 2x² cos2x.

    Now factoring:

    2x(sin 2x + x cos 2x)

    Then it's done.
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  3. #3
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    Re:

    Hi Zachb hope all is going well. I worked the problem out, then gave you for future reference an easy way to solve these types of derivatives. Just click on the link below.





    Best of luck!
    Last edited by qbkr21; April 29th 2007 at 07:57 PM.
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