Can anyone shed light on how the following simplification was achieved?
I had: $\displaystyle 4a^2 w^2 (coswt + cos2wt)^2 + 4a^2 w^2 (sin2wt - sinwt)^2 $
Which became:
$\displaystyle 8a^2 w^2 (1 + cos3wt) $
I expect there is a trig identity required but my mind is blank, help!