We have N a random variable from the (a,b,0) class distribution

which means that P_n = (a+b/n)^n * P_{n-1}

question 1:

Find E[N] as a function of a and b

question 2:

Find Var[N] as a function of a and b

Where E is the expected value

and Var is the variance.

Thank you for your help