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Math Help - X and Y have following joint CDF: ? 3 questions

  1. #1
    Junior Member plm2e's Avatar
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    X and Y have following joint CDF: ? 3 questions

    Suppose that X and Y have the following joint cumulative distribution function:

    F(x,y) = [1 - e^(-2x)] [1 - e^(-3y)] I(0,infinite)[x], I(0,infinite)[y]


    i. What does lim (y goes to infinite) F(2,y) denote?


    ii. What does lim (y goes to infinite) F(2,y) equal?


    iii. Find the joint probability density function fX,Y for X and Y.



    Any help with this problem will be appreciated. part iii in particular. thanks
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  2. #2
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    Quote Originally Posted by plm2e View Post
    Suppose that X and Y have the following joint cumulative distribution function:

    F(x,y) = [1 - e^(-2x)] [1 - e^(-3y)] I(0,infinite)[x], I(0,infinite)[y]

    Sorry but I don't understand your notation. In particular, what does I(0,infinite)[x], I(0,infinite)[y] mean?
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  3. #3
    Junior Member plm2e's Avatar
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    x goes from 0 to infinity, y goes from zero to infinity
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  4. #4
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    Quote Originally Posted by plm2e View Post
    x goes from 0 to infinity, y goes from zero to infinity
    What is being integrated? If you're integrating [1 - e^(-2x)] [1 - e^(-3y)] from x goes from 0 to infinity and y goes from zero to infinity then this does not define a joint cumulative distribution function.

    What you've posted still makes no sense (to me, anyway).
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