Question

(1-Cos2a)×(1-Cos2a)-3Sin2a

Answer 1

$(1 - cos(2 alpha ) (1 - cos(2 alpha ) - 3 sin(2 alpha ) = (1 - 1 + 2sin {}^{2} ( alpha ) ) {}^{2} - 6 sin( alpha ) cos( alpha ) = 4 { sin }^{2} alpha - 6 sin( alpha ) cos( alpha )$