Complex numbers in algebraic and polar form

9000039110

Level: 
C
Assuming \(z\in \mathbb{C}\), solve the following equation. \[ \left (1 + \mathrm{i}\sqrt{3}\right )z = 1 -\mathrm{i}\sqrt{3} \]
\(z = -\frac{1} {2} -\frac{\sqrt{3}} {2} \mathrm{i}\)
\(z = \frac{\sqrt{3}} {2} + \frac{1} {2}\mathrm{i}\)
\(z = -\frac{1} {2} + \frac{\sqrt{3}} {2} \mathrm{i}\)
\(z = -\frac{\sqrt{3}} {2} + \frac{1} {2}\mathrm{i}\)

9000039108

Level: 
C
Assuming \(z\in \mathbb{C}\), solve the following equation. By \(\overline{z }\) the complex conjugate of \(z \) is denoted. \[ 2z -\mathrm{i}\, \overline{z} = 1 -\mathrm{i} \]
\(z = \frac{1} {3} -\frac{1} {3}\mathrm{i}\)
\(z = 1 + \mathrm{i}\)
\(z = -\frac{3} {5} + \frac{6} {5}\mathrm{i}\)
\(z = -\frac{1} {5} -\frac{3} {5}\mathrm{i}\)

9000039101

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

9000037509

Level: 
B
Given complex numbers \[ a = 3\left (\cos \frac{\pi } {3} + \mathrm{i}\sin \frac{\pi } {3}\right ),\quad b = \sqrt{2}\left (\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\right ) \] find the product \(ab\).
\(- 3\sqrt{2}\)
\(3\sqrt{2}\left (\cos \frac{\pi }{2} + \mathrm{i}\sin \frac{\pi }{2}\right )\)
\(3\sqrt{2}\left (\cos \frac{\pi }{2} -\mathrm{i}\sin \frac{\pi }{2}\right )\)
\(- 3\sqrt{2}\left (\cos \frac{\pi }{2} + \mathrm{i}\sin \frac{\pi }{2}\right )\)

9000037510

Level: 
B
Given complex numbers \[ a = \left (\cos \frac{\pi } {3} + \mathrm{i}\sin \frac{\pi } {3}\right ),\quad b = \sqrt{2}\left (\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\right ) \] find the quotient \(\frac{a} {b}\).
\(\frac{\sqrt{2}} {2} \left (\cos \left (-\frac{\pi } {3}\right ) + \mathrm{i}\sin \left (-\frac{\pi } {3}\right )\right )\)
\(\frac{\sqrt{2}} {2} \left (\cos \left (-\frac{\pi } {3}\right ) -\mathrm{i}\sin \left (-\frac{\pi } {3}\right )\right )\)
\(-\frac{\sqrt{2}} {2} \left (\cos \left (-\frac{\pi } {3}\right ) -\mathrm{i}\sin \left (-\frac{\pi } {3}\right )\right )\)
\(-\frac{\sqrt{2}} {2} \left (\cos \left (-\frac{\pi } {3}\right ) + \mathrm{i}\sin \left (-\frac{\pi } {3}\right )\right )\)

9000038601

Level: 
B
Find the polar form of the following complex number. \[ -\frac{1} {2} + \mathrm{i}\frac{\sqrt{3}} {2} \]
\(\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\)
\(\cos \frac{\pi } {3} + \mathrm{i}\sin \frac{\pi } {3}\)
\(\cos \left (-\frac{\pi }{3}\right ) + \mathrm{i}\sin \left (-\frac{\pi }{3}\right )\)
\(\cos \frac{3\pi } {2} + \mathrm{i}\sin \frac{3\pi } {2}\)

9000038602

Level: 
B
Find the polar form of the following complex number. \[ \frac{1} {2} + \mathrm{i}\frac{\sqrt{3}} {2} \]
\(\cos \frac{\pi }{3} + \mathrm{i}\sin \frac{\pi }{3}\)
\(\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\)
\(\cos \frac{3\pi } {2} + \mathrm{i}\sin \frac{3\pi } {2}\)
\(\cos \left (-\frac{\pi }{3}\right ) + \mathrm{i}\sin \left (-\frac{\pi }{3}\right )\)

9000038603

Level: 
B
Find the polar form of the following complex number. \[ \frac{\sqrt{2}} {2} + \mathrm{i}\frac{\sqrt{6}} {2} \]
\(\sqrt{2}\left (\cos \frac{\pi }{3} + \mathrm{i}\sin \frac{\pi }{3}\right )\)
\(\sqrt{2}\left (\cos \frac{2\pi } {3} + \mathrm{i}\sin \frac{2\pi } {3}\right )\)
\(2\left (\cos \frac{4\pi } {3} + \mathrm{i}\sin \frac{4\pi } {3}\right )\)
\(2\left (\cos \frac{3\pi } {2} + \mathrm{i}\sin \frac{3\pi } {2}\right )\)