Question

12sin^2 x + sin2x - 2cos^2 x = 4​

Answer 1

−2cos^2(X)=4
−12⋅(−2cos^2(X))=−12⋅4
cos^2(X)=−1:2⋅4
cos^2(X)=−1:1⋅2:1

cos^2(X)=−2