Testing for Convexity

41 Views Asked by At

enter image description here

Could somebody please explain the method for answering a question like this?

1

There are 1 best solutions below

1
On

It is easy to see, that the curve in definition of $A$ is an ellipse. Hence the set of extreme points of $A$ is this ellipse. Convexity is obvious: we use the same arguments as in the case of a closed ball.