Yay. Nevermind. I was somehow able to solve it. I found the marginal distribution of X, and replaced the fλ|X with fX|λ(x|λ)*f(λ)/f(x) and it worked. :)
Homework Statement
(Question is #6 on p.171 in An Introduction to Probability and Statistics by Ruhatgi & Saleh)
Let X have PMF Pλ{X=x} = λxe-λ/x!, x=0,1,2...
and suppose that λ is a realization of a RV Λ with PDF
f(λ)=e-λ, λ>0.
Find E(e-Λ|X=1)
The Attempt at a Solution
The...