If the tangents at 
and 
to the circumcircle of a triangle 
intersect
in a point 
,
then the circle with center 
and which passes through 
and 
is called the excosine circle, and cuts 
and 
in two points which are extremities of a diameter.
Excosine Circle
See also
Cosine CircleExplore with Wolfram|Alpha
References
Lachlan, R. An Elementary Treatise on Modern Pure Geometry. London: Macmillian, p. 75, 1893.Referenced on Wolfram|Alpha
Excosine CircleCite this as:
Weisstein, Eric W. "Excosine Circle." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ExcosineCircle.html