sin^4x+sin^2x-2/-cos^2x=2+sin^2x

Question

help please 

Answer 1

Do you want to prove LHS = RHS or solve it for X ?

Answer 2

Recall that cos²x + sin²x = 1.  So, sin²x - 1 = -cos²x

 

(sin⁴x + sin²x - 2)/(-cos²x) = (sin²x + 2)(sin²x - 1)/(-cos²x)

 

                                      = (sin²x + 2)(-cos²x)/(-cos²x)

 

                                      = sin²x + 2