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Homework Help: Improper Integral

  1. Apr 12, 2009 #1
    1. The problem statement, all variables and given/known data
    The integral from -infinity to infinity of (2-x^4)dv

    2. Relevant equations
    U substitution

    3. The attempt at a solution
    Dont know what to use as my "u" ?

    Can someone please help me out? Thank you in advance.
  2. jcsd
  3. Apr 12, 2009 #2
    You have a dv in your given integral. Is this the integral you mean?
    [tex]\int_{-\infty}^\infty (2-x^4) \,dx [/tex]
    If so, you do not need u-substitution here. Also, to compute an improper integral of this form you need to evaluate:
    [tex]\lim_{s\to\infty} \int_{-s}^s (2-x^4) \,dx [/tex]
  4. Apr 12, 2009 #3
    yes that the write integral . . so basically i just need to do regular anti derivate and then evaluate it ?
  5. Apr 12, 2009 #4
    so for an example like this you would just do a regular anti derivative and then substitute your "s" in for the infinities and then evaluate >?

    -Jay J-
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