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Homework Help: Simple line integral problem I cant seem to get

  1. Mar 19, 2009 #1
    I have to evaluate the line integral :
    [itex]\oint_{}^{} (2x + y)dx + xydy[/itex] between (-1,2) and (2,5)

    on the curve: [itex]y = x + 3[/itex]

    So, what I did was:
    [itex]\int_{-1}^{2} (3x+3)dx + \int_{2}^{5} (x^{2} + 3x)dx [/itex]

    However, this is wrong and im not sure why!
    Can someone please guide me?
    Thanks alot!
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Mar 19, 2009 #2


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    You are parametrizing the curve by the value of x which goes from -1 to 2. In BOTH parts. Since you've expressed the dy part of the integral in terms of x, why are you using the y limits there?
  4. Mar 19, 2009 #3
    Ahhh, thanks so much!
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