Algorithms for solving f(x) = 0
Question
For a differentiable function , describe numerical algorithms for finding a root of .
Short answer
Bisection, Newton-Raphson and the secant method. Bisection halves a sign-change bracket each step: guaranteed but only linear convergence. Newton uses , converging quadratically near a simple root but may diverge from a poor start. The secant method replaces by a finite difference of the last two iterates (order about ); hybrids such as Brent's method combine safety and speed.
Adapted from Zhou, A Practical Guide to Quantitative Finance Interviews, sec. 3.4 Important Calculus Methods, 'Newton's method B', p.44; question and answer rewritten by SelfMadeQuant.com.
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