Книга: Radical axis: Radical Axis, Circle, Locus, Bipolar Coordinates, Apollonian Circles, Power Center, Transitive Relation

High Quality Content by WIKIPEDIA articles! The radical axis (or power line) of two circles is the locus of points at which tangents drawn to both circles have the same length. For any point P on the radical axis, there is a unique circle centered on P that intersects both circles at right angles (orthogonally) conversely, the center of any circle that cuts both circles orthogonally must lie on the radical axis. In technical language, each point P on the radical axis has the same power with respect to both circles.