Algebra and Trigonometry 10th Edition

Published by Cengage Learning
ISBN 10: 9781337271172
ISBN 13: 978-1-33727-117-2

Chapter 4 - 4.3 - Conics - 4.3 Exercises - Page 337: 16


Focus: $(0,-\frac{1}{16})$ (Red point) Directrix: $y=\frac{1}{16}$ (Black line)

Work Step by Step

Parabola in the standard form with the vertex at origin (vertical axis): $x^2=4py$ $y=-4x^2$ $x^2=-\frac{1}{4}y$ That is: $4py=-\frac{1}{4}y$ $p=-\frac{1}{16}$ $(0,p)=(0,-\frac{1}{16})$ Directrix: $y=-p=\frac{1}{16}$
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