# What is the derivative of tanx^3?

The derivative is $3 {x}^{2} \cdot {\sec}^{2} \left({x}^{3}\right)$ where $\sec x$ is the secant function
$d \frac{\tan {x}^{3}}{\mathrm{dx}} = d \frac{{x}^{3}}{\mathrm{dx}} \cdot \frac{1}{\cos} ^ 2 \left({x}^{3}\right) = 3 {x}^{2} \cdot \left(\frac{1}{\cos} ^ 2 \left({x}^{3}\right)\right) = 3 {x}^{2} \cdot {\sec}^{2} \left({x}^{3}\right)$