Any complex number, x+ iy, can be written in exponential form, [tex]re^{i\theta}[tex] where and .

Yes, is correct. That same answer could be written [tex]8e^{5\pi/4}[tex] because .

DeMoivre's theorem: if , then which also works if n is a fraction: and you can get all n roots by repeatedly adding tobeforedividing by n.