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## Homework Statement

I am to prove (using the equations for gradient, divergence and curl in spherical polar coordinates) that vector field $$\mathbf{w}=w_{\psi}(r,\theta)\hat e_{\psi}$$ is solenoidal, find $$w_{\psi}(r,\theta)$$ when it's irrotational and find a potential in this case.

## Homework Equations

## The Attempt at a Solution

For vector field to be solenoidal, divergence should be zero, so I get the equation:

$$\nabla\cdot\mathbf{w}=\frac{1}{r\sin\theta}\frac{\partial w_{\psi}(r,\theta)}{\partial \psi}=0$$

For a vector field to be irrotational, the curl has to be zero. After substituting values into equation, I get:

$$\cos\theta\cdot w_{\psi}+\frac{\partial w_{\psi}}{\partial \theta}\cdot \sin\theta=0$$

and

$$w_{\psi}+\frac{\partial w_{\psi}}{\partial r}\cdot r=0$$.

Is it right? How to proceed?