Multivariable Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 0-53849-787-4
ISBN 13: 978-0-53849-787-9

Chapter 10 - Parametric Equations and Polar Coordinates - 10.6 Exercises - Page 708: 11

Answer

(a) e = 1 (b) Parabola (c) y = 2/3 (d) Image below: ---------------------

Work Step by Step

(a) $$r = \frac {2}{3 + 3sin(\theta)} \div \frac{3}{3} = \frac {2/3}{1 +sin(\theta)}$$ Based on the original equation: $$\frac{ed}{1 + esin(\theta)}$$ $$e = 1$$ (b) $e = 1 $, therefore, this equation represents a parabola. (c) The equation has a $+sin(\theta)$ and the focus is at (0,0), thus, the equation of the directrix must be in the "$y = c$" pattern. In this case: $c = d$: $$ed = 2/3 \longrightarrow d = \frac{2/3}{e} = \frac{2/3}{1} = 2/3 $$ $$y = 2/3$$ (d) Plot the points where $\theta = 0$, $\theta = \pi/2$, $\theta = \pi$ $$r = \frac {2}{3 + 3sin(0)} \longrightarrow (2/3, 0)$$ $$r = \frac {2}{3 + 3sin(\pi/2)} \longrightarrow (1/3, \pi/2)$$ $$r = \frac {2}{3 + 3sin(\pi)} \longrightarrow (2/3, \pi)$$ Draw a parabola that passes through these points.
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.