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Homework Help: Integration of y * sqrt function

  1. Apr 17, 2010 #1
    1. The problem statement, all variables and given/known data

    given: 3/8 * ∫ (y^3) *√((y^4)+9) dy the integral is from 0 - 2



    2. Relevant equations



    3. The attempt at a solution

    I have attempted the problem so far, it was a double integration and it is right up to here. I just cant figure out how to integrate this part.
     
  2. jcsd
  3. Apr 17, 2010 #2

    Mark44

    Staff: Mentor

    Looks like an ordinary substitution would work - u = y^4 + 9 ==> du = 4u^3*du
     
  4. Apr 17, 2010 #3
    Thankyou! worked a treat.
     
  5. Apr 17, 2010 #4

    Mark44

    Staff: Mentor

    So if you're working with double integrals and having trouble with ordinary substitutions, I would advise you to go back and review the integration techniques such as substitution, trig substitution, integration by parts, and partial fractions.
     
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