Powers and roots of complex numbers

9000070101

Level: 
A
Find the algebraic form of the complex number: \[ \left (\cos \frac{\pi } {4} + \mathrm{i}\sin \frac{\pi } {4}\right )^{3} \]
\(-\frac{\sqrt{2}} {2} + \mathrm{i}\frac{\sqrt{2}} {2} \)
\(-\frac{\sqrt{2}} {2} -\mathrm{i}\frac{\sqrt{2}} {2} \)
\(\frac{\sqrt{2}} {2} -\mathrm{i}\frac{\sqrt{2}} {2} \)
\(\frac{\sqrt{2}} {2} + \mathrm{i}\frac{\sqrt{2}} {2} \)

9000070102

Level: 
A
Evaluate the following complex number. \[ \left (\cos \frac{\pi } {3} + \mathrm{i}\sin \frac{\pi } {3}\right )^{10} \]
\(-\frac{1} {2} -\mathrm{i}\frac{\sqrt{3}} {2} \)
\(-\frac{\sqrt{3}} {2} -\frac{1} {2}\mathrm{i}\)
\(-\frac{\sqrt{3}} {2} + \frac{1} {2}\mathrm{i}\)
\(-\frac{1} {2} + \mathrm{i}\frac{\sqrt{3}} {2} \)