Derivatives-Problem of rate of change I'm studying applications of derivatives and I have the following problem about rate of change: A raindrop falls over a surface and generated waves of circular form such that the rate of change of the radius of the wave its 636.36 ft/s and expands along 1,1s. Find the area of the circle of maximum radius. My approach: let's call r the radius then the hypothesis means upsilon=dr/dt=636.36ft/s. By physics we have r=upsilont then r=636.36∗1,1=700ft is the maximum radius. Then A=pi∗r^2=pi∗(700)^2=1539380.40ft^2.

beobachtereb

beobachtereb

Answered question

2022-09-26

Derivatives-Problem of rate of change
I'm studying applications of derivatives and I have the following problem about rate of change:
A raindrop falls over a surface and generated waves of circular form such that the rate of change of the radius of the wave its 636.36 ft/s and expands along 1,1s. Find the area of the circle of maximum radius.
My approach: let's call r the radius then the hypothesis means v = d r d t = 636.36 f t / s. By physics we have r = v t then r = 636.36 1 , 1 = 700 f t is the maximum radius. Then A = π r 2 = π ( 700 ) 2 = 1539380.40 f t 2
Is my solution right?

Answer & Explanation

Kellen Blackburn

Kellen Blackburn

Beginner2022-09-27Added 8 answers

That is indeed correct.
P.S. Since you're solving this in the context of calculus, you may want to do it using principles of calculus (as opposed to algebra).
You had v = d r d t = 636.36, so
d r = v d t
To get the maximum radius, we want the r that was at the end of the time interval, which was from t=0 to t=1.1. So integrate (sum) both sides to get
r = 0 1.1 636.36 d t = 636.36 x | 0 1.1 = 636.36 ( 1.1 ) 636.36 ( 0 ) = 700
Then continue as you did to get the area.

Do you have a similar question?

Recalculate according to your conditions!

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?