Question

-2sin^2(pi/6-a)+6-2 cos^2(pi/6-a)

Answer 1

2(3-sin^2(pi/6-a)- cos^2(pi/6-a)) = 2(3-(sin^2(pi/6-a) + cos^2(pi/6-a))) = 2*(3 - 1) = 2*2 = 4.

Answer 2

спасибо )