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10.4 Polar Coordinates: Graphs

Symmetry tests, zeros, and maximum values used to sketch circles, cardioids, limaçons, rose curves, and lemniscates.

Algebra and Trigonometry 2e, 10.4 Polar Coordinates: Graphs

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21 exercises

Testing a Polar Equation for Symmetry

Test the equation r=2sinθ r = 2 \sin \theta for symmetry.

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10.4 Exercise 2

Test the equation for symmetry: r=−2cosθ. r = - 2 \cos \theta .

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Finding Zeros and Maximum Values for a Polar Equation

Using the equation in the example, find the zeros and maximum | r | \left|r\right| and, if necessary, the polar axis intercepts of r=2sinθ. r = 2 \sin \theta .

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10.4 Exercise 4

Without converting to Cartesian coordinates, test the given equation for symmetry and find the zeros and maximum values of | r |: \left|r\right| : r=3cosθ. r = 3 \cos \theta .

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10.4 Exercise 17

Describe the three types of symmetry in polar graphs, and compare them to the symmetry of the Cartesian plane.

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10.4 Exercise 19

What are the steps to follow when graphing polar equations?

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10.4 Exercise 21

What part of the equation determines the shape of the graph of a polar equation?

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10.4 Exercise 23

Test the equation for symmetry.

r=3−3cosθ r = 3 - 3 \cos \theta

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10.4 Exercise 25

Test the equation for symmetry.

r=3sin2θ r = 3 \sin 2 \theta

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10.4 Exercise 27

Test the equation for symmetry.

r=2θ r = 2 \theta

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10.4 Exercise 29

Test the equation for symmetry.

r= 2 θ r = \frac{2}{\theta}

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10.4 Exercise 31

Test the equation for symmetry.

r= 5sin2θ r = \sqrt{5 \sin 2 \theta}

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10.4 Exercise 71

Use a graphing utility to graph each pair of polar equations on a domain of [ 0,4π ] \left[0 , 4 \pi\right] and then explain the differences shown in the graphs.

r=θ,r=θ+sinθ r = \theta , r = \theta + \sin \theta

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10.4 Exercise 73

Use a graphing utility to graph each pair of polar equations on a domain of [ 0,4π ] \left[0 , 4 \pi\right] and then explain the differences shown in the graphs.

r=2sin( θ 2 ),r=θsin( θ 2 ) r = 2 \sin \left(\frac{\theta}{2}\right) , r = \theta \sin \left(\frac{\theta}{2}\right)

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10.4 Exercise 75

Use a graphing utility to graph each pair of polar equations on a domain of [ 0,4π ] \left[0 , 4 \pi\right] and then explain the differences shown in the graphs.

On a graphing utility, graph r=sin( 16 5 θ ) r = \sin \left(\frac{16}{5} \theta\right) on [ 0\left[\right. 0, 4π ]4 \pi \left]\right., [ 0\left[\right. 0, 8π ]8 \pi \left]\right., [ 0\left[\right. 0, 12π ] 12 \pi \left]\right., and [ 0\left[\right. 0, 16π ]. 16 \pi \left]\right. . Describe the effect of increasing the width of the domain.

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10.4 Exercise 77

Use a graphing utility to graph each pair of polar equations on a domain of [ 0,4π ] \left[0 , 4 \pi\right] and then explain the differences shown in the graphs.

On a graphing utility, graph each polar equation. Explain the similarities and differences you observe in the graphs.

r 1 =3sin(3θ) r 2 =2sin(3θ) r 3 =sin(3θ) \begin{matrix}r_{1} = 3 \sin \left(3 \theta\right) \\ r_{2} = 2 \sin \left(3 \theta\right) \\ r_{3} = \sin \left(3 \theta\right)\end{matrix}
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10.4 Exercise 79

Use a graphing utility to graph each pair of polar equations on a domain of [ 0,4π ] \left[0 , 4 \pi\right] and then explain the differences shown in the graphs.

On a graphing utility, graph each polar equation. Explain the similarities and differences you observe in the graphs.

r 1 =3θ r 2 =2θ r 3 =θ \begin{matrix}r_{1} = 3 \theta \\ r_{2} = 2 \theta \\ r_{3} = \theta\end{matrix}
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10.4 Exercise 81

Draw each polar equation on the same set of polar axes, and find the points of intersection.

r 1 =6−4cosθ, r 2 =4 r_{1} = 6 - 4 \cos \theta , r_{2} = 4

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10.4 Exercise 83

Draw each polar equation on the same set of polar axes, and find the points of intersection.

r 1 =1+cosθ, r 2 =3cosθ r_{1} = 1 + \cos \theta , r_{2} = 3 \cos \theta

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10.4 Exercise 85

Draw each polar equation on the same set of polar axes, and find the points of intersection.

r 1 = sin 2 ( 2θ )r_{1} = \sin^{2} \left(2 \theta\right), r 2 =1−cos( 4θ ) r_{2} = 1 - \cos \left(4 \theta\right)

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10.4 Exercise 87

Draw each polar equation on the same set of polar axes, and find the points of intersection.

r 1 2 =sinθ, r 2 2 =cosθ r_{1} ^{2} = \sin \theta , r_{2} ^{2} = \cos \theta

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Adapted from College Algebra © 2021 Rice University. Licensed under CC BY 4.0. Sources: College Algebra 2e, Algebra and Trigonometry 2e, Precalculus 2e, College Algebra with Corequisite Support 2e. Imported at revision 4922e46.