# Divergence homework problem help

1. Jul 19, 2014

### manimaran1605

1. The problem statement, all variables and given/known data

How divergence of r (cap)/ |r|^2 is equal to zero?

2. Relevant equations

r(cap)= x(cap)+y(cap)+z(cap)

|r|^2 as x^2+y^2+z^2

3. The attempt at a solution

I tried the problem and end up with with a different solution I took r(cap)= x(cap)+y(cap)+z(cap)
|r|^2 as x^2+y^2+z^2. Tell me where i went wrong?

where r(cap) is unit vector of r vector
|r|^2 is the square of modulus of r

2. Jul 19, 2014

Could you please provide the calculation that lead you to the wrong answer? It is hard to pinpoint where you went wrong otherwise.

3. Jul 19, 2014

### vela

Staff Emeritus
You didn't differentiate correctly. Show your work.

4. Jul 19, 2014

### manimaran1605

Here's my attempt to the problem

#### Attached Files:

• ###### 20140720_085120.jpg
File size:
23.1 KB
Views:
48
5. Jul 20, 2014

Well $\mathbf{\hat r} = \mathbf{\hat x} + \mathbf{\hat y} + \mathbf{\hat z}$ seems false. You have $\mathbf{r} = (x,y,z)$. Work from there.