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Homework Help: Help in integration

  1. Jun 9, 2008 #1
    can someone integrate that problem

    x^2 cos (x^5) dx

    i tried integration by parts but i didn't get anything
  2. jcsd
  3. Jun 9, 2008 #2
    There might be something wrong with the question if you are in an introductory course

    some mess:

    f =


    >> int(f,x)

    ans =


    >> f = x^2*(cos(x))^5

    f =


    >> int(f,x)

    ans =

  4. Jun 9, 2008 #3
    no there is nothing wrong with the problem and iam in what called in our country differentiation and integration 2 like calculus 3
    and the original problem is from my exam {{ and i didn't solve it but i'm curious }}

    given____ { int from 0 to 4 }{int from y^1/2 to 2 } cos(x^5) dx dy ____ reverse the order of integration and evaluate the resulting intgerals .

    after reversing , it will be ______ x^2 cos (x^5) dx _______ and the inequalities dosent matter
  5. Jun 9, 2008 #4


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    You reversed the order of integration. You intergrate with wrt y first, dydx.
    Last edited: Jun 9, 2008
  6. Jun 10, 2008 #5
    so what is the solution of the integration pls
  7. Jun 10, 2008 #6


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    Staff Emeritus
    Science Advisor
    Gold Member

    Are you sure it was [itex] \cos(x^5)[/itex]? You really couldn't integrate that on a test. The method for reversing the order of integration is fairly simple. You first need to sketch the area of integration on a graph and then find the limits for integrating over y with x constant and then the limits for integrating over x with y constant.
  8. Jun 11, 2008 #7
    i'm absolutely sure that it's int of x^2 cos(x^5) dx

    dose anyone have any idea ????????????
  9. Jun 11, 2008 #8
    What was the original question? We've already proved that the integral you post is too difficult!
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