Question

Упростите cos^4a + sin^2a* cos^2 a

Answer 1

(1+cos2a)²/4 +(1-cos2a)*(1+cos2a)/4=(1+2cos2a+cos²2a+1-cos²2a)/4=
=2(1+cos2a)/4=(sin²a+cos²a+cos²a-sin²a)/2=2cos²a/2=cos²a

Answer 2

Cos^4a+sin^2acos^2a=cos^2a (cos^2a+sin^a)= cos^2a