The simplest root-finding algorithm is the bisection method. It works when
f is a continuous function and it requires previous knowledge of two initial
guesses, a and b, such that f(a) and f(b) have opposite signs, then find the
midpoint of [a, b], and then decide whether the root lies on [a, (a + b)/2] or
[(a+b)/2, b]. Repeat until the interval is sufficiently small. By the intermediate