7(sin^2*11 - cos^2*11)/cos22

Question

7(sin^2*11 - cos^2*11)/cos22

Answer 1

7(sin^2 11 - cos^2 11)/cos22 = 7 ( 1  - cos^2 11 - cos^2 11) / (2cos^2 11 - 1) =

-7 (2 cos^2 11 - 1) / (2cos^2 11 - 1) = -7