1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Solid of revolution (should be simple)

  1. Jun 30, 2011 #1
    Hey. Thanks in advanced for the help. This site has helped me a lot through the years.

    1. The problem statement, all variables and given/known data

    Find the volume of the solid formed by rotating the area within y=e^x and y=sin x when 0<x<pi

    2. Relevant equations



    3. The attempt at a solution

    I've tried it like 10 times on the whiteboard, and did it quickly on a sheet of paper so someone call tell me where I'm going wrong...the answer is supposedly pi/8(e^(2pi)-1)

    Here's my work. http://min.us/mvfTL55 [Broken]
     
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Jun 30, 2011 #2

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    The anti-derivative if cos(x) is +sin(x), not -sin(x) .
     
  4. Jun 30, 2011 #3
    Are you sure that's where I made my mistake? The reason it became positive (I think) is not that I got the anti-derivative mixed up. It's because the negative sign outside the parenthesis canceled out the one before the pi*integral of cos2x/2
     
  5. Jun 30, 2011 #4

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Of course! You're right.

    What is the correct answer?

    What axis is this area to be revolved around?
     
  6. Jun 30, 2011 #5
    Around the x-axis. answer is pi/8(e^(2pi)-1)

    It looks kinda similar...but not quite.
     
  7. Jun 30, 2011 #6

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Your work looks good to me !!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Solid of revolution (should be simple)
  1. Solid of Revolution (Replies: 2)

  2. Solids of revolution (Replies: 3)

  3. Solid of Revolution (Replies: 1)

  4. Solids of revolution (Replies: 7)

  5. Solids of Revolution (Replies: 3)

Loading...