Calculus: Early Transcendentals 8th Edition

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

Chapter 13 - Section 13.1 - Vector Functions and Space Curves - 13.1 Exercises - Page 854: 27

Answer

The parametric equations describe a curve that spirals upwards. As \(t\) increases, the curve spirals around the cone with increasing radius.

Work Step by Step

\[ x=t\cos(t), \quad y=t\sin(t), \quad z=t \] We need to show that this curve lies on the cone defined by the equation: \[ x^2+y^2=z^2 \] Calculate \(x^2+y^2\): \[ x^2+y^2=(t\cos(t)+t\sin(t))^2 \\ x^2+y^2=t^2(\cos^2(t)+\sin^2(t)) \] Since \(\cos^2(t)+\sin^2(t)=1\) \[x^2+y^2=t^2\] Since \(z=t\), we have: \[ z^2=t^2\\ x^2+y^2=t^2 \quad and \quad z^2=t^2 \\ \] So we have: \[ x^2+y^2=z^2 \]
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.