Recall that sin(x1+x2)=sinx1cosx2+cosx1sinx2 and cos(x1+x2)=cosx1cosx2-sinx1sinx2.

Show that e^i(x1+x2)=e^(ix1)e^(ix2) using the formulas above.

So I got e^i(x1+x2)=cos(x1+x2)+isin(x1+x2)=

(cosx1cosx2-sinx1sinx2)+i(sinx1 cosx2+cosx1sinx2)=

cos(x2)*(e^(ix1))+sin(x2)*(icosx1-sinx1), but this is where I am stumped.

Any ideas how I can proceed.

Thanks