I'm looking for the E[XY] of the joint moment generating function of a couple of random variables (X,Y). We don't know if the variables are independent. I don't know how to solve the partial derivative ∂² E[e^(sX+tY)] ∂s ∂t
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What information do you have about the variables? – Graham Kemp Feb 03 '17 at 02:18
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I don't have any information, I think I need to find a general equation for the (X,Y) couple – h1gh5ive Feb 03 '17 at 02:36
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Do we at least know if continuous of discrete they are? – Graham Kemp Feb 03 '17 at 03:00
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I suppose they are continuous – h1gh5ive Feb 03 '17 at 03:01