Gopal Gopakumar
Last Activity: 8 Years ago
This equation can be written as (sin2x + cos2x )2 – 2sin2xcos2x
which is 1 – 2sin2xcos2x..... multiplying and dividing with 4 gives,
(4 – 8sin2xcos2x)/4 which using sin2@ identity can be written as
(4 – 2sin22x)/4 = (3 + 1 – 2sin22x)/4
which by cos2@ identity gives,
(3 + cos4x)/4 and hence is the simplified equation.
period od cos(n)x = 2pi/n
so period of cos4x = pi/2