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U substitution or substitution by parts?

  1. May 3, 2010 #1
    1. The problem statement, all variables and given/known data
    ∫〖e^√x/√x dx〗
    would this be a u substitution or a substitution by parts?

    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. May 3, 2010 #2

    Mark44

    Staff: Mentor

    I would go with an ordinary substitution. The other technique you mentioned is usually called integration by parts.
     
  4. May 3, 2010 #3
    oh oops I meant to say integration by parts. So would I let u= sqrt(x)?
     
  5. May 3, 2010 #4

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    That would be a good thing to try. What does that lead to?
     
  6. May 3, 2010 #5
    So if u= sqrt(x) du= 1/2 x^-1/2 and now I'm a little lost because the du doesn't look like it helps me.
     
  7. May 3, 2010 #6

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    Better written as

    [tex]du = \frac 1 {2\sqrt x}\, dx[/tex]

    Now take a look at what you are supposed to integrate. Does the integrand involve anything that looks like the above?
     
  8. May 3, 2010 #7
    Alright I think I see it but I want to check. Would I write it as 1/2 ∫〖e^u du〗?
     
  9. May 3, 2010 #8

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    Yes.

    BTW, what's the deal with the brackets and parentheses?
     
  10. May 3, 2010 #9
    Thanks so much for your help DH. I don't know the deal with the brackets and parentheses. I have been using microsoft word's equation writer because I'm not too sure how to use the equation writer on here. Thanks again!!
     
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