Answer
The derivative is $\pi/2*cos( theta )+sin(theta)$
Work Step by Step
Whenever two or more functions are being added or subtracted, the overall derivative would be the sum of the derivatives of every smaller function. The derivative of $\pi/2*sin(theta)$ would be $\pi/2*cos(theta)$ and the derivative of -cos(theta) would be +sin(theta); hence, the overall derivative would $\pi/2*cos( theta )+sin(theta)$.
