Thomas' Calculus 13th Edition

Published by Pearson
ISBN 10: 0-32187-896-5
ISBN 13: 978-0-32187-896-0

Chapter 3: Derivatives - Section 3.8 - Related Rates - Exercises 3.8 - Page 161: 1


$\dfrac{dA}{dt} = 2\pi r \dfrac{dr}{dt}$

Work Step by Step

Area of a circle, A can be determined as:$\pi r^2$, Thus, A = $\pi r^2$ On differentiation , we get: $\dfrac{dA}{dt}$ = $\dfrac{d\pi r^2}{dt}$ or, $\dfrac{dA}{dt} = 2\pi r \dfrac{dr}{dt}$ Hence, $\dfrac{dA}{dt} = 2\pi r \dfrac{dr}{dt}$
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.