For a wave described by:

A*sin(x)+B*sin(x-PI/3)

I'd like to describe it in terms of a single sine or cosine function.

It does reduces to A * sqrt(3) *sin(x-PI/6), but only if A=B

I can't seem to find any identity that would work if A is not equal to B though. Am I right in assuming that it's not possible to describe this wave in terms of a single sine or cosine function when A is not equal to B?