Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
A secant line is a straight line that intersects a curve at two points. It represents the average rate of change between those two points on the curve.
A tangent line is a straight line that touches a curve at only one point. It represents the instantaneous rate of change or slope of the curve at that specific point.
Slope refers to how steep or flat a line is. In terms of secant lines, it represents the ratio of vertical change (rise) to horizontal change (run) between two points on a curve.
Average rate of change measures how much one quantity changes on average compared to another quantity over an interval. In relation to secant lines, it represents the slope or rate of change between two points on a curve.