Calculus: Early Transcendentals 9th Edition

Published by Cengage Learning
ISBN 10: 1337613924
ISBN 13: 978-1-33761-392-7

Chapter 10 - Section 10.5 - Conic Sections - 10.5 Exercises - Page 708: 7

Answer

Vertex: $(4,-3)$ Focus: $(3\frac{1}{2},-3)$ Directrix: $x=4\frac{1}{2}$

Work Step by Step

Recall: The parabola $(y-b)^2=4p(x-a)$ has a vertex $(a,b)$, a focus $(a+p,b)$, and a directrix $x=-p+a$. We have $y^2+6y+2x+1=0$ or equivalently, $y^2+6y+9+2x-8=0$ $(y+3)^2+2(x-4)=0$ $(y+3)^2=-2(x-4)$ $(y-(-3))^2=-2(x-4)$ Then, $(a,b)=(4,-3)$ $4p=-2$ $p=-\frac{1}{2}$ So, the vertex is $(4,-3)$, the focus is $(3\frac{1}{2},-3)$, and the directrix $x=4\frac{1}{2}$. Sketch the graph:
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.