9000035801
Level:
A
Find the complex conjugate of the following complex number.
\[
\mathrm{i} + 3\mathrm{i}(2 -\mathrm{i})^{2} - 4(1 -\mathrm{i})^{3}
\]
\(20 - 18\mathrm{i}\)
\(20 - 24\mathrm{i}\)
\(20 + 18\mathrm{i}\)
\(- 8 + 26\mathrm{i}\)
Complex numbers in algebraic and polar form
9000035803
Level:
A
Given the complex number \(z = -1 + 2\mathrm{i}\),
find the imaginary part of the complex number
\(\frac{1}
{z}\).
\(-\frac{2}
{5}\)
\(\frac{1}
{2}\)
\(\frac{2}
{5}\)
\(-\frac{1}
{2}\)
9000035804
Level:
A
Find the algebraic form of the following complex number. By \(\overline{z }\) the complex conjugate of \(z \) is denoted.
\[
\overline{\overline{(2 + \mathrm{i}) }\; \overline{(3 + 2\mathrm{i}) } }
\]
\(4 + 7\mathrm{i}\)
\(8 + 7\mathrm{i}\)
\(8 - 7\mathrm{i}\)
\(4 - 7\mathrm{i}\)
9000035805
Level:
B
Given the complex numbers
\[
\text{$a = 2\left (\cos \frac{2\pi }
{3} + \mathrm{i}\sin \frac{2\pi }
{3}\right )$, $b = \sqrt{2}\left (\cos \frac{3\pi }
{4} + \mathrm{i}\sin \frac{3\pi }
{4}\right )$,}
\]
find the product \(ab\).
\(2\sqrt{2}\left (\cos \frac{17\pi }
{12} + \mathrm{i}\sin \frac{17\pi }
{12}\right )\)
\(2\sqrt{2}\left (\cos \frac{\pi }{2} + \mathrm{i}\sin \frac{\pi }{2}\right )\)
\(2\sqrt{2}\left (\cos \frac{5\pi }
{7} + \mathrm{i}\sin \frac{5\pi }
{7}\right )\)
\(2\sqrt{2}\left (\cos \frac{5\pi }
{12} + \mathrm{i}\sin \frac{5\pi }
{12}\right )\)
9000035806
Level:
B
Given the complex numbers
\[
\text{ $a = 2\left (\cos \frac{5\pi }
{3} + \mathrm{i}\sin \frac{5\pi }
{3}\right )$, $b = 3\left (\cos \frac{11\pi }
{6} + \mathrm{i}\sin \frac{11\pi }
{6} \right )$,}
\]
find the quotient \(\frac{a}
{b}\).
\(\frac{2}
{3}\left (\cos \frac{11\pi }
{6} + \mathrm{i}\sin \frac{11\pi }
{6} \right )\)
\(\frac{2}
{3}\left (\cos \frac{\pi }
{6} + \mathrm{i}\sin \frac{\pi }
{6}\right )\)
\(\frac{2}
{3}\left (\cos \frac{5\pi }
{6} + \mathrm{i}\sin \frac{5\pi }
{6}\right )\)
\(\frac{2}
{3}\left (\cos \frac{7\pi }
{6} + \mathrm{i}\sin \frac{7\pi }
{6}\right )\)
9000035710
Level:
A
Find the complex conjugate of \(z=\frac{3+\mathrm{i}}
{2-\mathrm{i}} + (\mathrm{i} + 1)(2 + \mathrm{i})\).
\(2 - 4\mathrm{i}\)
\(2 + 4\mathrm{i}\)
\(- 2 - 4\mathrm{i}\)
\(- 2 + 4\mathrm{i}\)
9000035807
Level:
A
Given the complex numbers \(a = 2 - 3\mathrm{i}\),
\(b = 1 + 2\mathrm{i}\), find the
quotient \(\frac{a}
{b}\).
\(-\frac{4}
{5} -\frac{7}
{5}\mathrm{i}\)
\(2 -\frac{3}
{2}\mathrm{i}\)
\(\frac{8}
{5} -\frac{7}
{5}\mathrm{i}\)
\(\frac{4}
{3} + \frac{7}
{3}\mathrm{i}\)
9000035706
Level:
A
Find the absolute value of the complex number
\(z = \frac{2+6\mathrm{i}}
{1-2\mathrm{i}}\).
\(2\sqrt{2}\)
\(2\sqrt{5}\)
\(2\)
\(2\sqrt{3}\)
9000035708
Level:
A
Find the imaginary part of the complex number
\(z=1 + 2\mathrm{i}^{12} + 3\mathrm{i}^{19} -\mathrm{i}^{22} + 2\mathrm{i}^{105}\).
\(- 1\)
\(- 5\)
\(1\)
\(4\)
9000035707
Level:
A
Find the real part of the complex number
\(z= 2 + 2\mathrm{i}^{2} + \mathrm{i}^{3} -\mathrm{i}^{4} + 2\mathrm{i}^{5}\).
\(- 1\)
\(1\)
\(5\)
\(- 3\)