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

Show that for the expectation values the following relations hold: [itex]d \langle x \rangle /dt =\langle p \rangle /m[/itex] and [itex]d \langle p \rangle /dt = - \langle d V/dx \rangle[/itex].

2. Relevant equations

[itex]\langle x \rangle = \int _{- \infty}^{\infty} \Psi ^* x \Psi dx[/itex].

3. The attempt at a solution

I'm trying to show the first relation. I think I have to do [itex]\frac{d}{dt} \left [ \int _{- \infty}^{\infty} \Psi ^* x \Psi dx \right ][/itex]. But I don't know how to evaluate the integral since Psi is unknown to me. I'm stuck here.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Quantum mechanics, expectation value

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**