 # Improve Your Expected Value Formula Skills with Practice Problems and Real-World Examples

Recent questions in Expected Value Formula Israel Young 2023-03-19

## The value of $\left(243{\right)}^{-\frac{2}{5}}$ is _______.A)9B)$\frac{1}{9}$C)$\frac{1}{3}$D)0 Lizeth Herring 2022-12-30

## If x varies directly as a square of y for y=6, x=72. Find x for y=9. remangavit79 2022-12-16

## What is the absolute value of $8$? kokoszzm 2022-06-27
## I found in many places that the average momentum of a particle is given by:$⟨p⟩={\int }_{-\mathrm{\infty }}^{\mathrm{\infty }}{\psi }^{\ast }\left(\frac{\hslash }{i}\right)\frac{\mathrm{\partial }\psi }{\mathrm{\partial }x}\phantom{\rule{mediummathspace}{0ex}}\mathrm{d}x$I think that it comes from considering the classical momentum:$⟨p⟩=m\frac{\mathrm{d}⟨x⟩}{\mathrm{d}t}$and that the expected value of the position is given by:$⟨x⟩={\int }_{-\mathrm{\infty }}^{\mathrm{\infty }}x\phantom{\rule{mediummathspace}{0ex}}{|\psi \left(x,t\right)|}^{2}\phantom{\rule{mediummathspace}{0ex}}\mathrm{d}x$But when replacing $⟨x⟩$ and differentiating inside the integral I don't know how to handle the derivatives of $\psi$ for getting the average momentum formula. Any suggestion? Davian Maynard 2022-05-26