(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Given y=xtanx, find y'' (second derivative)

2. Relevant equations

Uh... I'm not even sure if I'm using the right one....

d/dx(tanx) = sec^2x

3. The attempt at a solution

y=xtanx

y'= (x)(sec^2(x)) + (tanx)(1)

y'= xsec^2(x) + tanx

y'' = [(x)(2sec^3(x)) + sec^2(x)(1)] + sec^2x

y'' = 2xsec^3(x) + sec^2(x) + sec^2(x)

....

The key answer says it is supposed to be (2cosx + 2xsinx)/(cos^3(x))

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# Second derivative of xtanx?

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