A detailed derivation of sin ^ 2 (WT + ∮) = (1 / 2) [1-cos ^ 2 (WT + ∮]

A detailed derivation of sin ^ 2 (WT + ∮) = (1 / 2) [1-cos ^ 2 (WT + ∮]

From the square of cosine formula cos2a = 1-2 (Sina), the square of (sin (WT + $) = (1-cos2 (WT + $)) / 2 can be obtained