I am doing this problem and I am getting stuck at solving the equation(adsbygoogle = window.adsbygoogle || []).push({});

problem: Use the second derivative test to determine the concavity of the following function. y = x(cosx) at x = pi/3

solution: y' = -xsinx + cosx

y'' = -xcosx - 2sinx = 0

and then i did

-xcosx = 2sinx ( i dont know if this is correct)

and then I am stuck... i dont know how to proceed.

please help

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# Homework Help: Solve this equation please

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