A community for students. Sign up today!
Here's the question you clicked on:
 0 viewing
 9 months ago
The radius, r, of the base of a circular cylinder increases by 2 feet per second while the height, h, decreases by 1 foot per second. How fast is the surface area of the cylinder changing when the height of the cylinder is 50 feet and the radius of the base is 40 feet?
I got \(440\pi\) square feet per second, am I right?
 9 months ago
The radius, r, of the base of a circular cylinder increases by 2 feet per second while the height, h, decreases by 1 foot per second. How fast is the surface area of the cylinder changing when the height of the cylinder is 50 feet and the radius of the base is 40 feet? I got \(440\pi\) square feet per second, am I right?

This Question is Closed

geerky42
 9 months ago
Best ResponseYou've already chosen the best response.0My work: __________________________________________________________________ Since it is known that surface area of this cylinder is \(SA = 2\pi r^2 + 2\pi rh\)\[\dfrac{dSA}{dt} = 4\pi r\dfrac{dr}{dt} + 2\pi \dfrac{dr}{dt} +2\pi r \dfrac{dh}{dt}\]We are given that r = 40, h = 50, \(\dfrac{dr}{dt} = 2\), \(\dfrac{dh}{dt} = 1\) I plugged in these values and I got \(\boxed{440\pi}\) __________________________________________________________________ But there is no option for \(440\pi\), I'm not sure if there is typo in options or I made mistake somewhere in my work...

klimenkov
 9 months ago
Best ResponseYou've already chosen the best response.2Your solution seems to be okay, (but you forgot \(h\) in the second addend). Maybe there is a typo or the surface area is computed without bottom and top of the cylinder.. Better to ask the person that has gived you this task.
Ask your own question
Ask a QuestionFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.