# How do you find the derivative of tan^2x?

I found: $y ' = 2 \tan \frac{x}{\cos} ^ 2 \left(x\right)$
You can use the Chain Rule to deal first with the ${\left(\right)}^{2}$ and then with $\tan$. Remember that the derivatve of $\tan \left(x\right)$ is $\frac{1}{\cos} ^ 2 \left(x\right)$.
$y ' = \textcolor{red}{2 \cdot \tan \left(x\right)} \cdot \textcolor{b l u e}{\frac{1}{\cos} ^ 2 \left(x\right)} = 2 \tan \frac{x}{\cos} ^ 2 \left(x\right)$