# Thread: Poisson distribution with expected value Question

1. ## Poisson distribution with expected value Question

I need help with this one question:

Let N have a Poisson distribution. Find the expected value of 1/(1+N). Your answer should be a simple formula involving the parameter of the Poisson distribution.

2. my attempt:

where:
a=lambda
k=n

The significant steps are:
*re-organising the limits of the sum (second line from the end)
*recognising the power series representation of e^a