# Vector Identity (del operator)

1. Jul 19, 2012

### racnna

i am completely lost as to how to go from
$$p^ \frac{1}{m}∇p$$
to
$$\frac{m}{m+1} ∇p^\frac{m+1}{m}$$

Last edited: Jul 19, 2012
2. Jul 19, 2012

### Muphrid

In general, the chain rule should tell you that,

$$\nabla p^a = a p^{a-1} \nabla p$$

Choose an appropriate value for $a$ and see what happens.

3. Jul 19, 2012

### racnna

oh wow.....nice trick