A community for students. Sign up today!
Here's the question you clicked on:
 0 viewing
 one year ago
Calc Problem: Help please!
Find the volume of the solid obtained by rotating the region bounded by y=9 x^2, x = 1, and y = 0, about the xaxis.
 one year ago
Calc Problem: Help please! Find the volume of the solid obtained by rotating the region bounded by y=9 x^2, x = 1, and y = 0, about the xaxis.

This Question is Closed

campbell_st
 one year ago
Best ResponseYou've already chosen the best response.1ok the the formula for rotating about the x axis is \[V = \pi \int\limits_{a}^{b} y^2 dx\] so the values of a and b are and then y = 0 the corresponding value of x is x = 0... so that means a = 0 and b = 1 the graph looks like dw:1386823443784:dw so you are looking at \[V = \pi \int\limits_{0}^{1} (9x^2)^2 dx\] so just simply the (9x^2)^2 then integrate and evaluate between x = 1 and x = 0

pdd21
 one year ago
Best ResponseYou've already chosen the best response.0Thank you so much that helped clear up my confusion! there was another problem I was stuck on, but instead of it being respect to xaxis it's respect to the yaxis. > Find the volume of the solid obtained by rotating the region bounded by y=x^2 , y = 0, and x = 3, about the yaxis. how do I solve this problem? @campbell_st

campbell_st
 one year ago
Best ResponseYou've already chosen the best response.1ok... so find the upper value of the curve at x = 3 so y = 9 this is similar to before dw:1386823955174:dw the values of a and b are a = 0 and b = 9 so you are looking at \[V = \pi \int\limits_{a}^{b} x^2 dy\] you have your equation in terms of x^2 so its \[V = \pi \int\limits_{0}^{9} y dy\] hope it makes sense

pdd21
 one year ago
Best ResponseYou've already chosen the best response.0so, \[V=\pi \int\limits_{0}^{9} (x^2)\] I don't seem to be getting the correct answer ;/ @campbell_st

pdd21
 one year ago
Best ResponseYou've already chosen the best response.0nvm! I caught my mistake! haha

campbell_st
 one year ago
Best ResponseYou've already chosen the best response.1well because you are rotating about the y axis you integrate with respect to y \[V = \pi \int\limits_{0}^{9} y dy = 2\pi[\frac{y}{2}]^9_{0}\]

campbell_st
 one year ago
Best ResponseYou've already chosen the best response.1oops forgot the y^2... \[V = \pi \int\limits_{0}^{9} y dy = \pi [\frac{y^2}{2}]^9_{0}\]
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.