Question

Помогите пожалуйста
Cos2a+ sin^2а

Answer 1

cos2a = 2cos^2a - 1 = 1 - 2sin^2a = cos^2a - sin^2a

cos2a + sin^2a =  cos^2a - sin^2a + sin^2a = cos^2a 

Answer 2

$cos2a+sin ^{2} a=cos ^{2} a-sin ^{2} a+sin^{2} a=cos ^{2} a$