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Thread: double integral to find area

  1. #1
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    double integral to find area

    find ∫ y dA , where R is the region between (y^2) + (x-2)^2 = 4 and y = x in the first quadrant

    i have skteched out the diagram and did it,. But my ans is 13/ 3 rather than 4/3 , is the ans provided wrong ? P/s : ans provided is 4/3 ...
    double integral to find area-img_20160909_105339.jpg
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  2. #2
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    Re: double integral to find area

    Hey xl5899.

    You might want to check your limit for the A2 part - it should be 4 - (x+2)^2 not 4 - x + 2.

    See if you can adjust the limits and make sure they correspond to the A2 part [draw a diagram and post it if you need to] before re-trying the evaluation of the integral.
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  3. #3
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    Re: double integral to find area

    There are two regions "between $\displaystyle (x- 2)^2+ y^2= 4$ and y= x", one above y= x and one below. Which do you mean?
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    Re: double integral to find area

    Quote Originally Posted by chiro View Post
    Hey xl5899.

    You might want to check your limit for the A2 part - it should be 4 - (x+2)^2 not 4 - x + 2.

    See if you can adjust the limits and make sure they correspond to the A2 part [draw a diagram and post it if you need to] before re-trying the evaluation of the integral.
    well , after correction , my A2 = 8/3 , so A 1= 4/3 , A1 + A2 = 4 , which is still not 4/3 , which part is wrong ?
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