Something simple: I'd like
TrigExpand[Sin[3n-3]] to return
Sin[3n]Cos-Cos[3n]Sin instead of
-Cos[n]^3 Sin+3 Cos Cos[n]^2 Sin[n]+3 Cos[n] Sin Sin[n]^2-Cos Sin[n]^3.
Is there a way to get Mathematica to expand the addition/sum without expanding the multiplier(s)?
(The reason: I'm working with Fourier series and I want to be able to see things as combinations of
Sin[a n] and