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10.3 Polar Coordinates

Locating a point by radius and angle, converting to and from rectangular form, and rewriting equations between the systems.

Algebra and Trigonometry 2e, 10.3 Polar Coordinates

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30 exercises

10.3 Exercise 7

Write the polar coordinates ( −1, 2π 3 ) \left(- 1 , \frac{2 \pi}{3}\right) as rectangular coordinates.

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Rewriting a Cartesian Equation in Polar Form

Rewrite the Cartesian equation y=3x+2 y = 3 x + 2 as a polar equation.

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10.3 Exercise 12

Rewrite the Cartesian equation y 2 =3− x 2 y^{2} = 3 - x^{2} in polar form.

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10.3 Exercise 15

Rewrite the polar equation r=2sinθ r = 2 \sin \theta in Cartesian form.

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Rewriting a Polar Equation in Cartesian Form

Rewrite the polar equation r=sin( 2θ ) r = \sin \left(2 \theta\right) in Cartesian form.

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10.3 Exercise 17

How are polar coordinates different from rectangular coordinates?

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10.3 Exercise 19

Explain how polar coordinates are graphed.

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10.3 Exercise 21

Explain why the points ( −3, π 2 ) \left(- 3 , \frac{\pi}{2}\right) and ( 3,− π 2 ) \left(3 , - \frac{\pi}{2}\right) are the same.

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10.3 Exercise 23

Convert the given polar coordinates to Cartesian coordinates. Remember to consider the quadrant in which the given point is located when determining θ \theta for the point.

( 5,π ) \left(5 , \pi\right)

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10.3 Exercise 25

Convert the given polar coordinates to Cartesian coordinates. Remember to consider the quadrant in which the given point is located when determining θ \theta for the point.

( −3, π 6 ) \left(- 3 , \frac{\pi}{6}\right)

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10.3 Exercise 27

Convert the given Cartesian coordinates to polar coordinates with r>0,0≤θ<2π. r > 0 , 0 \leq \theta < 2 \pi . Remember to consider the quadrant in which the given point is located.

( 4,2 ) \left(4 , 2\right)

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10.3 Exercise 29

Convert the given Cartesian coordinates to polar coordinates with r>0,0≤θ<2π. r > 0 , 0 \leq \theta < 2 \pi . Remember to consider the quadrant in which the given point is located.

( 3,−5 ) \left(3 , −5\right)

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10.3 Exercise 31

Convert the given Cartesian coordinates to polar coordinates with r>0,0≤θ<2π. r > 0 , 0 \leq \theta < 2 \pi . Remember to consider the quadrant in which the given point is located.

( 8,8 ) \left(8 , 8\right)

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10.3 Exercise 33

Convert the given Cartesian equation to a polar equation.

y=4 y = 4

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10.3 Exercise 35

Convert the given Cartesian equation to a polar equation.

y=2 x 4 y = 2 x^{4}

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10.3 Exercise 37

Convert the given Cartesian equation to a polar equation.

x 2 + y 2 =3x x^{2} + y^{2} = 3 x

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10.3 Exercise 39

Convert the given Cartesian equation to a polar equation.

x 2 − y 2 =3y x^{2} - y^{2} = 3 y

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10.3 Exercise 41

Convert the given Cartesian equation to a polar equation.

x 2 =9y x^{2} = 9 y

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10.3 Exercise 43

Convert the given Cartesian equation to a polar equation.

9xy=1 9 x y = 1

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10.3 Exercise 45

Convert the given polar equation to a Cartesian equation. Write in the standard form of a conic if possible, and identify the conic section represented.

r=4cosθ r = 4 \cos \theta

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10.3 Exercise 47

Convert the given polar equation to a Cartesian equation. Write in the standard form of a conic if possible, and identify the conic section represented.

r= 6 cosθ+3sinθ r = \frac{6}{\cos \theta + 3 \sin \theta}

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10.3 Exercise 49

Convert the given polar equation to a Cartesian equation. Write in the standard form of a conic if possible, and identify the conic section represented.

r=3cscθ r = 3 \csc \theta

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10.3 Exercise 51

Convert the given polar equation to a Cartesian equation. Write in the standard form of a conic if possible, and identify the conic section represented.

r 2 =4secθcscθ r^{2} = 4 \sec \theta \csc \theta

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10.3 Exercise 53

Convert the given polar equation to a Cartesian equation. Write in the standard form of a conic if possible, and identify the conic section represented.

r 2 =4 r^{2} = 4

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10.3 Exercise 55

Convert the given polar equation to a Cartesian equation. Write in the standard form of a conic if possible, and identify the conic section represented.

r= 3 cosθ−5sinθ r = \frac{3}{\cos \theta - 5 \sin \theta}

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10.3 Exercise 85

Use a graphing calculator to find the rectangular coordinates of ( 2,− π 5 ). \left(2 , - \frac{\pi}{5}\right) . Round to the nearest thousandth.

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10.3 Exercise 87

Use a graphing calculator to find the polar coordinates of ( −7,8 ) \left(- 7 , 8\right) in degrees. Round to the nearest thousandth.

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10.3 Exercise 89

Use a graphing calculator to find the polar coordinates of ( −2,0 ) \left(- 2 , 0\right) in radians. Round to the nearest hundredth.

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10.3 Exercise 91

Describe the graph of r=asecθ;a<0. r = a \sec \theta ; a < 0.

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10.3 Exercise 93

Describe the graph of r=acscθ;a<0. r = a \csc \theta ; a < 0.

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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.