和弦sec和切线之间的区别

Chord vs Secant vs Tangent

Chord, secant, and tangent are lines intersecting curved lines. These are basic geometric constructs with interesting mathematical properties.

What is a Chord?

In a plane (2D Geometry), a line segment joining two points on a curve is called a chord. The term is often used to describe a line segment with its ends lying on the circumference of a circle. But it can also describe line segments drawn on ellipses and conic sections.

Among many others, chords of a circle exhibits following properties:

• If the lengths of two chords on the same circle are equal, the chords are lying at the same distant from the center.
• Diameter is a chord which is passing through the center, and it is the chord with the maximum length.
• If two angles are inscribed on the same chord and on opposite sides of the chord, then inscribed angles are supplemental.

What is a Secant?

A secant line is a line passing through two points of a curved line. Sometimes it is simply called a “secant”. However, in common usage, it refers to a line passing through two points of a circle. A chord can be considered as an interval on a secant line.

What is a Tangent?

A tangent line is a line that just touches a plane curve. Tangent can be considered as a special case of a secant line, where the two points on the curve are infinitely close (or overlap). Tangent has interesting properties and uses in mathematics.

What is the difference between Chord, Tangent and Secant?

• A chord is a line segment and both secant and tangents are straight lines.

• Chord is a line segment with the end points lying on a curve while a secant is a line passing through exact two points on a curve.

• A tangent is a line that just touches and passes through a point on a curve. It is a special case of secant where the two points on the curve overlap.