# Four-derivative expression help

1. Mar 30, 2008

### ercagpince

1. The problem statement, all variables and given/known data
I need to take the derivative of this expression explicitly

2. Relevant equations
$$\partial_{\mu}Ae^{(-i/\hbar)x\bullet p}u(p)$$

3. The attempt at a solution
I tried to take the derivative of it by taking the derivatives of components of the momentum four vector "p".
However, I got stuck while trying to recombine the expression left from derivation.

Last edited: Mar 30, 2008
2. Mar 30, 2008

### pam

$$\partial_{\mu}Ae^{(-i/\hbar)x\bullet p}u(p) =Ae^{(-i/\hbar)x\bullet p}u(p)[-i\hbar\partial_{\mu}(x^{\nu}p_{\nu})]$$,
which should be easy.

Last edited: Mar 30, 2008
3. Mar 30, 2008

### ercagpince

thanks a lot!