sin^4
(1-cos^2)^2
(1-cos)^2(1+cos)^2
(1-cos)(1-cos)(1+cos)(1+cos)
sin^2(x) = (1-cos(2x))/2
so,
sin^4(x) = (1 - cos(2x))^2/4
= (1 - 2cos(2x) + cos^2(2x))/4
= (1 - 2cos(2x) + (1 - cos(4x))/2)/4
= (1 - 2cos(2x) + 1/2 - cos(4x)/2)/4
= (2 - 4cos(2x) + 1 - cos(4x))/8
= (3 - 4cos(2x) - cos(4x))/8
don't know which way you wanted to go there.
Rewrite the expression so that it involves the sum or difference of only constants and sines and cosine to the 1st power
(sinx)^4
1 answer