#math/numerical #flashcards/math The secant method is numerical method for approximating the[[Function Root | root]] of a function. Its done by taking two known points on the function, drawing a secant line through them and finding where that line's x intercept. $ x_{r} = \frac{x_{0} \cdot f(x_{1}) - x_{1}\cdot f(x_{0})}{f(x_{1}) - f(x_{0})} $ The formula is arrived by constructing a line through the two points, via slope calculation, and setting that line to 0. This is used in my old App Ad's bidding teams [[Root Finder Bidding Algorithm]]