Question

could you possibly help with this one. find the exact value of the expression cos pi/3+ sin pi/2

Answer 1

\[\cos(\alpha +\beta)=\cos(\alpha)\cos(\beta)-\sin(\alpha )\sin(\beta)\]
use
\[\cos(\frac{\pi}{3})=\frac{1}{2}, \cos(\frac{\pi}{2})=0,\sin(\frac{\pi}{3})=\frac{\sqrt{3}}{2}, \sin(\frac{\pi}{2})=1\]