Electrostats, Gauss Theorem qusetion: Struck in middle

1. Jul 7, 2012

PrashntS

1. The question is to find the volume charge density. Given is non uniform, but spherically symmetric electric field, E=K.r4, K being a constant. Original question can be viewed in image:

* Question no. 53

2. Relevant equations

3. The attempt at a solution

Tried solving so many times. Once, I got half the answer I should have got!
Solution steps are attached.:

I got struck at the last equation,:
4Kεπr6=∫ ρ.dV
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jul 7, 2012

Dr_Stirk

Use gauss law in differential rather than integral form. 1/r^2*d/dr(r^2*E)=rho/epsilon