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Homework Help: Need help with setting up 2 double integrals

  1. Mar 29, 2009 #1
    1. The problem statement, all variables and given/known data

    I'm trying to find the CDF of e^-y.

    The cdf of any f(x,y) is [tex]\int^x_{-\infty} \int^y_{-\infty} f(u,v) dv du[/tex]

    where u and v are just dummy variables. I need to consider 2 cases: 1) 0<x<y and 2) 0 < y < x. In other words I need to do 2 double integrals using the general set up of a CDF.

    2. Relevant equations

    3. The attempt at a solution

    [tex]\int^x_0\int^y_x e^{-v} dv du [/tex] This case is when 0<x<y

    [tex]\int^x_0\int^x_y e^{-v} dv du [/tex] This case is when 0<y<x

    Did I set these up correctly? Because a friend of mine had 2 different answers, and I made a mistake somewhere. Thank you.
  2. jcsd
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