Question

2sin(пи-альфа)*cos(пи/2-альфа)

Answer 1

$2sin( \pi - \alpha )*cos( \frac{ \pi }{2}- \alpha )=2sin \alpha *sin \alpha =2sin^2 \alpha$

Answer 2

2sin(π-α)·cos(π/2-α)=2sinα·sinα=2sin²α