Question

cos^2(720-x)+sin^2(540+x)

Answer 1

$mathtt{cos^2(720а-x)+sin^2(540а+x)=cos^2(2pi-x)+sin^2(frac{3pi}{2}+x)=}\mathtt{cos^2x+(-cosx)^2=cos^2x+cos^2x=2cos^2x=cos2x+1}$