derivative of e^z/cos(z)

Question

I cannot remember how to incorporate e^z with the cos(z)

Answer 1

Let y=e^z/cos(z)=(e^z)sec(z),

dy/dz=(e^z)sec(z)+(e^z)sec(z)tan(z) by the product rule.

So the derivative is (e^z)sec(z)(1+tan(z)).