I'm new to mathematica. How would I plot the following functions in the polar complex plane?
$$ \phi={-k\over 2\pi r}\cos(\theta_0-\theta) $$
and
$$ \psi={-k\over 2\pi r}\sin(\theta_0-\theta) $$
Please provide the function calls if possible. I realize that I need to pick values for $k$ and $\theta_0$. It would be even better if someone knew how to sketch the flow.