Hello: I have 3 components of the Navier equation. One of them is this:

$\mu\left(\dfrac{\partial v\_x}{\partial y} + \dfrac{\partial v\_y}{\partial x}\right) = \tau\_{xy} = \tau\_{yx}$

Can anyone help me convert this to cylindrical coordinates?

Hint: The answer is: $\mu\left[r\dfrac{\partial}{\partial r}\left(\dfrac{v\_\theta}{r}\right) + \dfrac{1}{r}\left(\dfrac{\partial v\_r}{\partial \theta}\right)\right]$