Parallel and Series AC Sources

We know that it is very easy to calculate DC series and parallel sources because there is no phase difference but how we calculate ac sources in series and parallel also what happened when they have different phases.

A little bit mathematics..

What happens ?

Consider Phasor Representation.

A*exp(j*ph)=A1*exp(j*ph1) + A2*exp(j*ph2)

You can easily find out A and ph geometrically.