Precalculus: Mathematics for Calculus, 7th Edition

by Stewart, James; Redlin, Lothar; Watson, Saleem

Published by Brooks Cole

ISBN 10: 1305071751

ISBN 13: 978-1-30507-175-9

Chapter 11 - Review - Test - Page 835: 1

Answer

Focus: $(0,-3)$ Directrix: $y=3$

Work Step by Step

Equation of a parabola with vertical axis and vertex at origin: $x^2=4py$ $x^2=-12y$ $4p=-12$ $p=-3$ Focus: $F(0,p)=(0,-3)$ Directrix: $y=-p=3$

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