Question

Помогите!!
cos^2(п-a)+cos^2(3п/2-a)

Answer 1

$cos^2(pi - alpha )+cos^2(frac{3pi}{2}- alpha )=cos^2 alpha +sin^2 alpha =1\\\P.S.; ; ; cos(pi - alpha )=-cos alpha ; ,\\cos(frac{3pi}{2}- alpha )=-sin alpha$