30 БАЛЛОВ (sin^2 a - cos^2 a)^2+4 sin ^2 a cos^2 a

Question

30 БАЛЛОВ
(sin^2 a - cos^2 a)^2+4 sin ^2 a cos^2 a

Answer 1

(sin^2a-cos^2a)^2+4sin^2a*cos^2a=sin^4a-2sin^2a*cos^2a+cos^4a+4sin^2a*cos^2a=sin^4a+2sin^2a*cos^2a+cos^4a=(sin^2a+cos^2a)^2=1