(ii) 1+i1+i1+i r=∣z∣=12+12=2 r=|z|=\sqrt{1^2+1^2}=\sqrt{2}r=∣z∣=12+12=2 Since x>0x>0x>0 and y>0y>0y>0, θ=π4\theta=\frac{\pi}{4}θ=4π. 1+i=2(cosπ4+isinπ4)\boxed{1+i=\sqrt{2}\left(\cos\frac{\pi}{4}+i\sin\frac{\pi}{4}\right)}1+i=2(cos4π+isin4π)