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

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Answer 1 · 2018-03-08T20:00:59

Use #sin^2x = 1- cos^2x#.

RHS:

#(1 - cos^2x)(2 + 3cos^2x)#

#2 - 2cos^2x + 3cos^2x - 3cos^4x#

#2 + cos^2x- 3cos^4x#

LHS:

#2 + cos^2x - 3cos^4x#

LHS = RHS

Hopefully this helps!