Trigonometry (11th Edition) Clone

$-3\sqrt 2+3i\sqrt 2$
$6$ cis $135^{\circ}$=$6(\cos135^{\circ}+i\sin135^{\circ})$ It is known that $\cos135^{\circ}=-\frac{\sqrt 2}{2}$ and $\sin135^{\circ}=\frac{\sqrt 2}{2}$ Substituting these values in the expression and solving: $6(\cos135^{\circ}+i\sin135^{\circ})=6(-\frac{\sqrt 2}{2}+\frac{\sqrt 2}{2}i)=-3\sqrt 2+3i\sqrt 2$