Помогите срочно! 1/2(sin^2 15°- cos^2 15°)/4 cos 30°

Question

Помогите срочно! 1/2(sin^2 15°- cos^2 15°)/4 cos 30°

Answer 1

1) cos^2 15-sin^2 15=cos30=корень(3)/2 2)(cos15+sin15)^2=cos^2 15+2cos15*sin 15+sin^2 15=1+sin30=1+1/2=3/2