Accedmychevron_right11thchevron_rightmathchevron_rightComplex Numberschevron_rightExercise 1.5

(ii) 1+i1+i

r=z=12+12=2 r=|z|=\sqrt{1^2+1^2}=\sqrt{2}

Since x>0x>0 and y>0y>0, θ=π4\theta=\frac{\pi}{4}.

1+i=2(cosπ4+isinπ4)\boxed{1+i=\sqrt{2}\left(\cos\frac{\pi}{4}+i\sin\frac{\pi}{4}\right)}