The image of a circle under the [url=https://en.wikipedia.org/wiki/Joukowsky_transform]Joukowski transformation[/url] [math]f\left(z\right)=\frac{1}{2}\left(z+\frac{1}{z}\right)[/math].[br]Try changing the radius of the circle (r) or moving its center (A).[br][br][Prob. 2.1.6 of Saff and Snider, Fundamentals of Complex Analysis, 3rd ed.]