Intersections of circles in Cartesian plane
[xout,yout] = circcirc(x1,y1,r1,x2,y2,r2)
[xout,yout] = circcirc(x1,y1,r1,x2,y2,r2) finds
the points of intersection (if any), given two circles, each defined
by center and radius in x -y coordinates.
In general, two points are returned. When the circles do not intersect
or are identical,
NaNs are returned.
When the two circles are tangent, two identical points are returned. All inputs must be scalars.