10.5E: Polar Form of Complex Numbers (Exercises)
- Page ID
- 56119
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)For the following exercises, find the absolute value of each complex number.
28. \(-2+6 \mathbf{i}\)
29. \(4-3 \mathbf{i}\)
Write the complex number in polar form.
30. \(5+9 \mathbf{i}\)
31. \(\frac{1}{2}-\frac{\sqrt{3}}{2} \mathbf{i}\)
For the following exercises, convert the complex number from polar to rectangular form.
32. \(z=5 \operatorname{cis}\left(\frac{5 \pi}{6}\right)\)
33. \(z=3 \operatorname{cis}\left(40^{\circ}\right)\)
For the following exercises, find the product \(z_{1} z_{2}\) in polar form.
34.
\(z_{1}=2 \operatorname{cis}\left(89^{\circ}\right)\)
\(z_{2}=5 \operatorname{cis}\left(23^{\circ}\right)\)
35.
\(z_{1}=10\) cis \(\left(\frac{\pi}{6}\right)\)
\(z_{2}=6 \operatorname{cis}\left(\frac{\pi}{3}\right)\)
For the following exercises, find the quotient \(\frac{z_{1}}{z_{2}}\) in polar form.
36. \(z_{1}=12 \operatorname{cis}\left(55^{\circ}\right)\)
\(z_{2}=3 \operatorname{cis}\left(18^{\circ}\right)\)
37. \(z_{1}=27 \operatorname{cis}\left(\frac{5 \pi}{3}\right)\)
\(z_{2}=9 \operatorname{cis}\left(\frac{\pi}{3}\right)\)
For the following exercises, find the powers of each complex number in polar form.
38. Find \(z^{4}\) when \(z=2\) cis \(\left(70^{\circ}\right)\)
39. Find \(z^{2}\) when \(z=5\) cis \(\left(\frac{3 \pi}{4}\right)\)
For the following exercises, evaluate each root.
40. Evaluate the cube root of \(z\) when \(z=64\) cis \(\left(210^{\circ}\right)\).
41. Evaluate the square root of \(z\) when \(z=25\) cis \(\left(\frac{3 \pi}{2}\right)\).
For the following exercises, plot the complex number in the complex plane.
42. \(6-2 \mathbf{i}\)
43. \(-1+3 \mathbf{i}\)