Question

упростите выражение 1-cos2a

Answer 1

1-cos 2α = 1 -(cos²α-sin²α) = 1-cos²α+ sin²α = sin²α+sin²α = 2 sin²α

Answer 2

$1-cos2a=sin ^{2} a+cos ^{2} a-cos ^{2} a+sin ^{2} a= \\ \\ =sin ^{2} a+sin ^{2} a=2sin ^{2} a$