1. Not finding help here? Sign up for a free 30min 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!

Integration qns

  1. Dec 5, 2008 #1
    The question asks me to integrate x^2 sin x dx and then use it to find the exact value of the integration of abs ( x^2 sin x dx) with upper limit of pi/2 and lower limit of -pi/2.

    I have found the integration of x^2 sin x dx which is -x^2 cosx + 2xsinX + 2 cosx + C

    but after putting in the upper limits and lower limits i get the answer 2pi, where have i gone wrong because my first part is correct but the second part is different from the answer given.
  2. jcsd
  3. Dec 5, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    For what values of x is x2 sin x positive and for what values of x is it negative? Remember that |a|= a if a is positive and |a|= -a if a is negative. You cannot just evaluate x2 cosx + 2xsinX + 2 cosx + C at -pi/2 and pi/2.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Integration qns
  1. Kinematics qns (Replies: 4)

  2. Integral ? (Replies: 10)

  3. Integral of (Replies: 4)