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Math Help - calculus and trigonometry

  1. #1
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    calculus and trigonometry

    If f(x) = (ax + b) sinx + (cx +d ) cosx
    find constants a, b, c, d, such that f'(x) = xcosx

    How do I do this?

    thanks
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  2. #2
    Member Miss's Avatar
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    Quote Originally Posted by differentiate View Post
    If f(x) = (ax + b) sinx + (cx +d ) cosx
    find constants a, b, c, d, such that f'(x) = xcosx

    How do I do this?

    thanks
    Find the derivative and set it equal to x \, cos(x). Then, solve the last equation for a,b,c and d.
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