(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

First off, this is my first time posting here so please excuse any editing mistakes or guidelines I may have overlooked.

This is problem 1.17(c) from Griffiths,Introduction to Quantum Mechanics2nd edition. It reads: [tex]\Psi[/tex](x, 0) = A(a^2 - x^2), -a[tex]\leq[/tex]x[tex]\leq[/tex]a. [tex]\Psi[/tex](x, 0) = 0, otherwise. What is the expectation value for p? (Note that you cannot get it from p = md<x>/dt. Why not?)

2. Relevant equations

So far we've derived the expression <p>=[tex]\int[/tex][tex]\Psi[/tex]*([tex]\frac{h}{i}[/tex][tex]\frac{d}{dx}[/tex])[tex]\Psi[/tex]dx

3. The attempt at a solution

I found the expectation value for position to be <x>=0. Also, t=0. These seem to explain why I can't get <p> from md<x>/dt. But since the function is not complex I can't see how to interpret the above expression for <p>. The operator acts on the real part, but there is no imaginary part to deal with. Any clues on how to interpret this?

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

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Expectation value for p

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