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Improper Integral

  • #1

Homework Statement


The integral from -infinity to infinity of (2-x^4)dv


Homework Equations


U substitution


The Attempt at a Solution


Dont know what to use as my "u" ?



Can someone please help me out? Thank you in advance.
 

Answers and Replies

  • #2
537
3
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]
 
  • #3
yes that the write integral . . so basically i just need to do regular anti derivate and then evaluate it ?
 
  • #4
26
0
[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]
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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