Complex No's P6

How do you add 2complex no's together that are expressed in exponential form? ie. z1=2e^(i.pi/4) and z2=e^(i.-3pi/4) what is z1 + z2?

Thanks

Put them in the x+iy form first using

r exp(it) = r cos t + i r sin t

and then add them component-wise.

so u mean:
z1=2cos(pi/4) + 2i.sin(pi/4) and z2=cos(-3pi/4) + i.sin(-3pi/4)

but how can i add 2cos something to cos something else? I know that cos(a+b)=cosacosb - sinasinb, but not what to do when there's a multiple of cos? Thanks for all ur help