圆内切三角形及其在仿射变换下的不变性

The Triangle in the Circle and the Stability under the Change of Projecting the Triangle on the other Coordinate

圆内切三角形在仿射变换下变为椭圆内切三角形 .文中证明了在仿射变换确定后 ,根据仿射变换保持结合性的性质 ,圆内切于三角形的三切点经仿射变换后仍为三角形与内切椭圆的切点 。

Under the change of the triangle in the circle which project the triangle on the other coordinate,the triangle will become the one in ellipse.After the change has been decided,according to the combination character of the change,the three points which the triangle touch the circle are still the ones which the triangle touch the ellipse when projecting the triangle on the other coordinate.This kind of ellipse is the only one.