Tangent line and circle is a word in the field of mathematics. A straight line and a circle are tangent, and they have only one thing in common, which is called tangency. Comparing the distance d from the center of the circle to the straight line with the radius r of the circle, the definition of equation and tangent can be proved.
The positional relationship between straight line and circle
There are three positional relationships between a line and a circle: intersection, tangency and separation.
Intersection, Chinese vocabulary. The definition is that two straight lines cross each other and intersect at a point.
If a straight line intersects a curve at two points, and the two points are infinitely close and tend to overlap, then the straight line is the tangent of the curve at that point. In junior high school mathematics, if a straight line is perpendicular to the radius of a circle and passes through the outer end of the radius of the circle, it is said that the straight line is tangent to the circle.
Tangency is the positional relationship between a circle on a plane and another geometric shape.
Separation means separation from each other.