\sigma = 5.8e7 \\ E = [Ex,Ey,Ez] = [0,0,1] \\ J = [Jx,Jy,Jz] = \sigma E \\ R = \frac{1}{{\int {\frac{{J \cdot J}}{\sigma }} d\Omega }} \\

I have recently started using NGSolve.

I would like to do the above integral calculations in NGSolve. However, I do not know how to do it.

```
sigma = 5.8e7
mu = 4*pi*1e-7
E = CoefficientFunction([0,0,1])
J = sigma*E
R_denominator = LinearForm(fes)
R_denominator += J*J/sigma *dx
R = 1/R_denominator
```

I have tried with the above code, but I get an error.

**TypeError: unsupported operand type(s) for /: ‘int’ and ‘ngsolve.comp.LinearForm’**

Can someone please provide a solution?