# Creation operator problem

Anyone having an idea of how to solve problem 3a) file:///C:/Users/Administrator/Downloads/handin1%20(2).pdf ?

I've been stuck for a great while but have not idea.

## Answers and Replies

on part 3b) is it correct to argue that since you integrate away the x-dependence in the number operator that according to the heisenberg equation [H,N]=0 since both the partial derivative and total derivative of N is zero?

DEvens