Question

3sin²x-1 если cos²x=0.9

Answer 1

3 sin²x - ( sin² x + cos² x ) = 3 sin²x - sin² x - cos²x = 2 sin²x - cos²x

Answer 2

Cos^2 = 0.9, To 2 sin^2 - 0,9 => 2 sin^2 = 0,9; sin^2 = 0,45