# Proving the expectation value of any eigenvalue function

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1. Mar 18, 2017

### Cocoleia

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
When I take the second formula, multiply by it's conjugate and then by x and do the integral of the first formula, I get 0, and not L/2, for <x>. Am I missing a formula ?
The complex conjugate of the exponential part multiplied by the exponential part simplifies to 1, and when I do the integral I end up with 0.

2. Mar 18, 2017

### kuruman

3. Mar 18, 2017

### Cocoleia

-infinity and +infinity, as in the first formula (the orange background)

4. Mar 18, 2017

### kuruman

What is the size of the "box" the particle is in?

5. Mar 18, 2017

### Cocoleia

L? so would it be from 0 to L ?

6. Mar 18, 2017

### kuruman

Right. The particle is confined from 0 to L.