Complex numbers in algebraic and polar form

9000038605

Level: 
B
Find the polar form of the following complex number. \[ -\frac{\sqrt{5}} {2} + \mathrm{i}\frac{\sqrt{15}} {2} \]
\(\sqrt{5}\left (\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\right )\)
\(\sqrt{5}\left (\cos \frac{\pi }{3} + \mathrm{i}\sin \frac{\pi }{3}\right )\)
\(\sqrt{5}\left (\cos \frac{2\pi } {5} + \mathrm{i}\sin \frac{2\pi } {5}\right )\)
\(\sqrt{5}\left (\cos \frac{3\pi } {2} + \mathrm{i}\sin \frac{3\pi } {2}\right )\)

9000038606

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

9000038609

Level: 
B
Find the algebraic form of the following complex number. \[ 5\left (\cos \frac{3\pi } {4} + \mathrm{i}\sin \frac{3\pi } {4}\right ) \]
\(-\frac{5\sqrt{2}} {2} + \mathrm{i}\frac{5\sqrt{2}} {2} \)
\(\frac{5\sqrt{2}} {2} -\mathrm{i}\frac{5\sqrt{2}} {2} \)
\(\frac{5} {2} + \mathrm{i}\frac{5} {2}\)
\(\frac{5} {2} -\mathrm{i}\frac{5} {2}\)

9000039101

Level: 
B
Find the polar form of the complex number \(z=\frac{\mathrm{i}^{14}-1} {\mathrm{i}^{9}+1} \).
\(\sqrt{2}\left (\cos \frac{3\pi } {4} + \mathrm{i}\sin \frac{3\pi } {4}\right )\)
\(\sqrt{2}\left (\cos \frac{5\pi } {4} + \mathrm{i}\sin \frac{5\pi } {4}\right )\)
\(\sqrt{2}\left (\cos \frac{\pi }{4} + \mathrm{i}\sin \frac{\pi }{4}\right )\)
\(\sqrt{2}\left (\cos \frac{7\pi } {4} + \mathrm{i}\sin \frac{7\pi } {4}\right )\)

9000070110

Level: 
B
Given \(z_{1} = 4\left (\cos \frac{5} {3}\pi + \mathrm{i}\sin \frac{5} {3}\pi \right )\) and \(z_{2} = 2\left (\cos \frac{1} {6}\pi + \mathrm{i}\sin \frac{1} {6}\pi \right )\), evaluate \(\frac{z_{1}} {z_{2}} \).
\(- 2\mathrm{i}\)
\(4\mathrm{i}\)
\(\mathrm{i}\)
\(-\frac{1} {2}\mathrm{i}\)