- #1

fluidistic

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## Homework Statement

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].

## Homework Equations

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

## 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.