AI engineering glossary · Calculus optimisation
What is secant line?
Secant line: A straight line through two distinct points on a curve. Its slope is the average rate of change between them. As the two points move together, it approaches the tangent line, which is how the derivative is built from a limit.
Secant line: an example
On f(x) = x^2, the secant through x = 1 and x = 3 passes through (1, 1) and (3, 9), so its slope is (9 - 1) / (3 - 1) = 4.
Related terms
More Calculus optimisation terms
- Second-order approximation
- Second-order condition
- Sharpness-aware minimisation
- Simulated annealing
- Stationary point
- Step decay
- Stochastic gradient descent
- Strong convexity
Where you learn it
Secant line is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.