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Thread: Double integral problem

  1. #1
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    Double integral problem

    I ahve the question \int\int_D f(x,y) dxdy, where f(x,y)=xy^2 and D is the region in the first quadrant D bounded by the curves y = x^2 and x = y^2.

    And i think im right in saying that this is the same as
    \int^{\sqrt{x}}_{-\sqrt{x}} \int^{\sqrt{y}}_{-\sqrt{y}} xy^2 dxdy
    but when i do the first integral it equals 0 so i dont know what to do with the next
    Last edited by renlok; Apr 20th 2010 at 04:54 AM. Reason: fixing latex
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  2. #2
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    Your limits are wrong
    The integral is:
    \int_{0}^{1} \int_{y^2}^{\sqrt{y}} xy^2 \, dx \, dy

    For the double integral over general region, the limits of the outer integral should be constants ..
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  3. #3
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    oh right ok but how do you know what the integral limit are supposed to be?
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  4. #4
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    What is the first step to solve a double integral over general region?
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  5. #5
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    oh i get it know i watched
    YouTube - Calculating Double Integrals over General Regions
    and i was just thinking about the limits wrong thanks
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