The document discusses the bisection method, a numerical method for finding the roots of a polynomial function. The bisection method works by repeatedly bisecting an interval where the function changes sign and narrowing in on a root. It involves finding an interval [a,b] where f(a) and f(b) have opposite signs, taking the midpoint x1, and discarding half of the interval based on the sign of f(x1). This process is repeated, halving the interval width each time, until a root is isolated within the desired accuracy. An example applying the bisection method to find the roots of f(x) = x^3 + 3x - 5 on the interval [1,2