Calculus: Early Transcendentals 8th Edition

Published by Cengage Learning
ISBN 10: 1285741552
ISBN 13: 978-1-28574-155-0

Chapter 12 - Section 12.6 - Cylinders and Quadric Surfaces - 12.6 Exercises - Page 840: 15

Answer

Hyperboloid of One Sheet directed along \(x\)-axis.

Work Step by Step

We can rearrange the terms for it to be in standard form: \[ 9y^2+4z^2=x^2+36 \\ -x^2+9y^2+4z^2=36 \\ -\frac{x^2}{36}+\frac{9y^2}{36}+\frac{4z^2}{36}=1 \\ \] Evaluated at \(x=0\): \[ -\frac{(0)^2}{36}+\frac{9y^2}{36}+\frac{4z^2}{36}=1 \\ \frac{y^2}{4}+\frac{z^2}{9}=1 \\ \frac{y^2}{(2)^2}+\frac{z^2}{(3)^2}=1 \\ \] Ellipse of radius \(2\) along the \(y\)-axis and \(3\) along the \(z\)-axis. Evaluated at \(x=\pm 2\): \[ -\frac{(\pm6)^2}{36}+\frac{9y^2}{36}+\frac{4z^2}{36}=1 \\ -1+\frac{y^2}{4}+\frac{z^2}{9}=1 \\ \frac{y^2}{4}+\frac{z^2}{9}=2 \\ \frac{y^2}{8}+\frac{z^2}{18}=1 \\ \frac{y^2}{2\sqrt{2}}+\frac{z^2}{3\sqrt{2}}=1 \\ \] Ellipse of radius \(2\sqrt{2}\) along the \(y\)-axis and \(3\sqrt{2}\) along the \(z\)-axis.
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