Calculus (3rd Edition)

Published by W. H. Freeman
ISBN 10: 1464125260
ISBN 13: 978-1-46412-526-3

Chapter 12 - Parametric Equations, Polar Coordinates, and Conic Sections - 12.3 Polar Coordinates - Exercises - Page 617: 3

Answer

(a) $\left( {r,\theta } \right) = \left( {1,0} \right)$ (b) $\left( {r,\theta } \right) = \left( {2\sqrt 3 ,\frac{\pi }{6}} \right)$ (c) $\left( {r,\theta } \right) = \left( {2\sqrt 2 ,\frac{{3\pi }}{4}} \right)$ (d) $\left( {r,\theta } \right) = \left( {2,\frac{{2\pi }}{3}} \right)$

Work Step by Step

Use the conversion formula from rectangular coordinates to polar coordinates given by $r = \sqrt {{x^2} + {y^2}} $, ${\ \ \ }$ $\theta = {\tan ^{ - 1}}\left( {\frac{y}{x}} \right)$. (a) Since $\left( {x,y} \right) = \left( {1,0} \right)$, we have $r = \sqrt {1 + 0} $, ${\ \ \ }$ $\theta = {\tan ^{ - 1}}\left( {\frac{0}{1}} \right)$. So, $\left( {r,\theta } \right) = \left( {1,0} \right)$. (b) Since $\left( {x,y} \right) = \left( {3,\sqrt 3 } \right)$, we have $r = \sqrt {9 + 3} $, ${\ \ \ }$ $\theta = {\tan ^{ - 1}}\left( {\frac{{\sqrt 3 }}{3}} \right)$. So, $\left( {r,\theta } \right) = \left( {2\sqrt 3 ,\frac{\pi }{6}} \right)$. (c) Since $\left( {x,y} \right) = \left( { - 2,2} \right)$, we have $r = \sqrt {4 + 4} $, ${\ \ \ }$ $\theta = {\tan ^{ - 1}}\left( {\frac{2}{{ - 2}}} \right)$. So, $\left( {r,\theta } \right) = \left( {2\sqrt 2 ,\frac{{3\pi }}{4}} \right)$. (d) Since $\left( {x,y} \right) = \left( { - 1,\sqrt 3 } \right)$, we have $r = \sqrt {1 + 3} $, ${\ \ \ }$ $\theta = {\tan ^{ - 1}}\left( {\frac{{\sqrt 3 }}{{ - 1}}} \right)$. So, $\left( {r,\theta } \right) = \left( {2,\frac{{2\pi }}{3}} \right)$.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.