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Triple Integral

  1. May 24, 2017 #1
    • Moved from a technical forum and thus no template
    Here on problem #13 i am getting a false solution when only taking the volume of the region in quadrant 1 and multiplying it by 4. The later photo contains the correct solution which is obtained by taking the volume of the entire region. Can someone explain to me why the former is incorrect.
    image.jpg
    image_1.jpg
    image_2.jpg
     
  2. jcsd
  3. May 24, 2017 #2

    LCKurtz

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    Just because you are calculating a triple integral, it doesn't mean you are calculating a volume. If the integrand was ##1##, you would be, and your method would be correct. But your integrand is ##x^2e^y##, and ##e^y## is not symmetric about ##y=0##. So you don't get the same answer for each quadrant.
     
  4. May 25, 2017 #3

    Ray Vickson

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    Your images are unreadable. Type out your work if you really want help.
     
  5. May 27, 2017 #4
    I tried the problem myself. Is anyone else getting ##\frac{8}{3}e^{-1}##?
     
  6. May 27, 2017 #5

    LCKurtz

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    Yes, that's correct.
     
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