What is tangent definition?

In geometry, a tangent is defined as a straight line that touches a curve or a surface at a single point. The point of contact between the tangent line and the curve or surface is called the point of tangency. The tangent to a curve or surface at a point is perpendicular to the normal vector at that point. In trigonometry, the tangent function is defined as the ratio of the length of the opposite side of a right triangle to the length of the adjacent side. The tangent function is widely used in mathematics, physics, engineering, and other fields to model and solve a variety of problems involving angles, slopes, and rates of change.