Question

How do you verify the identity `2+cos^2x-3cos^4x=sin^2x(3+2cos^2x)`?

Answer 1

see below

Explanation:

Left Hand Side;

`2+cos^2 x - 3 cos^4 x = (1-cos^2x)(2+3cos^2x)`--> factors

use identity; `sin^2 x + cos ^2 x =1`

`=sin^2 x (2+3 cos ^2 x)`

`:.=` Right Hand Side