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Find the derivative of y= xcos(y)?

I have been trying to figure this out for a while and I can't figure it out, could anyone help me please?

it tells me y'=?

1 Answer

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  • 9 years ago
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        You need to use implicit differentiation.

    ——> Note: d/dx{  cosy } = -  siny • (dy/dx) = -  ý • siny

             y = x • cosy ... use the product rule, where: dy/dx = ý

             ý = -  x ý siny  +  cosy ... now solve for ý

       ý + x ý siny = cosy

       ý • (1 + x siny) = cosy

             ý = ( cosy) ⁄ (1 + x siny)

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