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Homework Help: Double integral yx

  1. May 23, 2010 #1
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. May 23, 2010 #2

    gabbagabbahey

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    No, you are integrating over both [itex]y[/itex] and [itex]x[/itex], so your answer shouldn't have [itex]x[/itex] in it. Why not show us your steps...
     
    Last edited by a moderator: May 4, 2017
  4. May 23, 2010 #3
    His x limit of integration includes an x, so I think this is the right answer. I suspect it might be the wrong integral, however. :)
     
  5. May 23, 2010 #4
    Ok, I'll post the steps... BTW Can I just ask how one writes integrals on forums so those so they aren't a terrible pain to read? :)

    @hgfalling: Do you think there was a typo in text or did I make a really dumb mistake?

    Edit: I've went to wolfram alpha and got the same result. Should I in the future use similar notation to that accepted by wolfram?

    http://img717.imageshack.us/img717/7077/integral2.png [Broken]

    Uploaded with ImageShack.us
     
    Last edited by a moderator: May 4, 2017
  6. May 23, 2010 #5
    @gabbagabbahey: Your signature is most helpfull! :)
     
  7. May 23, 2010 #6

    tiny-tim

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    Hi SimpliciusH! :smile:

    have an integral: ∫ and try using the X2 tag just above the Reply box :wink:)

    You may have fooled Wolfram, but you can't fool us o:)

    you can't integrate over a variable and then put the variable back in as a limit of integration …

    0kx f(x) dx doesn't make sense.
     
  8. May 23, 2010 #7

    gabbagabbahey

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    Are you sure the integral isn't [tex]\int_0^a\int_0^{kx}xy^2dydx[/tex]? As tinytim said, it is very bad notation to have an integral over [itex]x[/itex] and have [itex]x[/itex] in your integration limits.
     
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