Question

Evaluate:-
$\underset{0}{\overset{\pi /2}{\int }}\sin xdx$

Answer 1

${\int }_0^{\frac{\pi }{2}}\sin xdx$

$={[-\cos x]}_0^{\frac{\pi }{2}}$

$=-\cos \frac{\pi }{2}+\cos 0$

$=1$