Tangent

Definition of tangent:

A tangent to a curve at a point is a straight line that touches the curve at that point.

Equation of the tangent to a curve:

y = mx + c

Example of tangent:

The line AB is a tangent to the circle at point P. 

 

A tangent line to a circle contains exactly one point of the circle.A tangent to a circle is at right angles to the radius of the circle at its point of contact.