Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • School
  • explain solution rd sharma class 12 chapter 12 derivatives as a rate measure exercise fill in the blanks question 12 maths

explain solution rd sharma class 12 chapter 12 derivatives as a rate measure exercise fill in the blanks question 12 maths

Answers (1)

best_answer

Answer:\frac{dA}{dt}=12\pi \; cm^{2}/sec

Hint: Here we use the formula of area of circle (A) with radius r is given by

Given:A=\pi r^{2}

Solution:    \frac{dA}{dt}=\frac{d\left ( \pi r^{2} \right )}{dt}\times \frac{dr}{dt}=2\pi r\frac{dr}{dt}                     .......[by chain rule]

It is given that

                    \frac{dr}{dt}=3\; cm/s

               \therefore \frac{dA}{dt}=2\pi r(3)=6\pi r

Thus, when r=2 cm

               \therefore \frac{dA}{dt}=6\pi(2)=12\pi \; cm^{2}/s

Posted by

infoexpert26

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

Similar Questions

Trending Articles/News

anam-khan

CBSE Class 12 board exams 2025 to have 50% competency-based questions; no change in 10th
anam-khan

CBSE Class 12 board exams 2024 over; expected result date, trends of last 10 years

Latest Question