**4.1. Introduction **

Roots of the equation are the solution (values of x) of the equation f(x)=0. They can be real or complex. The later are seldom computed, because they rarely have physical significance, except for complex roots of polynomial equation. An equation may have any number of (real) roots or no roots at all. Iterative procedures are needed to find the roots by estimating a starting point. To prevent failure to converge the root, prior bracketing the root (determine its lower and upper bounds) is highly advisable.