# The operator of momentum (layman question)

1. May 17, 2014

### paulzhen

I found two "forms" of it:

p=$\frac{\hbar}{i}$$\frac{d}{dx}$

p=-i$\hbar$$\frac{d}{dx}$

how could they be the same??

2. May 17, 2014

### ZapperZ

Staff Emeritus
Multiply the right hand side of the first equation with i/i.

Zz.

3. May 17, 2014

### paulzhen

oh...yes thanks a lot