Answer
(a) $z=\sqrt 2(\cos\frac{3\pi}{4}+i\cdot \sin\frac{3\pi}{4})$
(b) $z=\sqrt 3+i$
(c) $1+i$, $\sqrt 2(\cos\frac{\pi}{4} + i\cdot \sin\frac{\pi}{4} )$
Work Step by Step
(a) The complex number $z=-1+i$ in polar form is $z=\sqrt 2(\cos\frac{3\pi}{4}+i\cdot \sin\frac{3\pi}{4})$
(b) ... in rectangular form is $z=\sqrt 3+i$
(c) ... in rectangular form as $1+i$ or in polar form as $\sqrt 2(\cos\frac{\pi}{4} + i\cdot \cos\frac{\pi}{4} )$
