Hi, I've got this problem with the solutions but I dont understand how to get from line 1 to line 2
I've attached the solution.
Im not sure why the sum to infinity of x.lamda^x results in lambda.e^lambda
Thanks in advance for any help clarifying.
Hi, I've got this problem with the solutions but I dont understand how to get from line 1 to line 2
I've attached the solution.
Im not sure why the sum to infinity of x.lamda^x results in lambda.e^lambda
Thanks in advance for any help clarifying.