Perform the Indicated Operation $5\left(\cos 270^{\circ}+i \sin 270^{\circ}\right) \cdot 4\left(\cos 30^{\circ}+i \sin 30^{\circ}\right)$

Essay

Perform the indicated operation. Give the answer in rectangular form.
(a) $5\left(\cos 270^{\circ}+i \sin 270^{\circ}\right) \cdot 4\left(\cos 30^{\circ}+i \sin 30^{\circ}\right)$
(b) $\frac{2 \operatorname{cis} 45^{\circ}}{\operatorname{cis} 90^{\circ}}$
(c) $(5-2 i)^{3}$
(d) Find the fourth roots of $-\sqrt{2}+i \sqrt{2}$ . Leave your answers in trigonometric form.