Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Area in between two curves

  1. May 28, 2012 #1
    Find the area of the region bounded by the following curves:

    y=x2-5x and y=3-x2


    So, using simultaneous equations I found the points of intersection (x = -0.5 and x = 3). The book agrees with me on that.

    I then performed the following:


    = -2x2+5x+3

    I then integrated that:


    I then subtracted the result when I substitute -0.5 from the result I get when I substitute 3. The book claims the answer is 2.655 but, no matter how hard I try I keep getting (271/24)

    Can anyone help me here please?

  2. jcsd
  3. May 28, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The work you showed so far is correct. Unfortunately I get 343/24 = 14.29 which doesn't agree with either of yours. Your book's answer is obviously wrong; clearly too small for the area enclosed.
  4. May 28, 2012 #3
    Hi! Thanks a lot for your response. I must be making some calculation error! When I try using the graphic calculator to find the integral it gives me 14.29, so, yeah, you should be right. I will try again.

    Thanks once again,
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook