Table of Contents

What is the Newton Raphson Method(NR)?

How to find the square root of a number using Newton Raphson method? This method falls in the category of open bracketing methods. It is also called the method of tangents as it determines the root of an equation by drawing the tangent to the function at initial guess. This method converges very fast and it fails only when the derivative of the function at the initial guess become equal to zero.

Derivation of NR method

There are two approaches to derive the formula for this method.

Using Taylor’s series
Using Graphical Interpretation

Taylor’s series use for deriving Newton Raphson Formula

Let x0 be the initial guess and the value of the function at this point is f(x0). Lets assume that x0+h be the next value or better approximation to the root of the function f(x)=0 where h is very very small. Then according to Taylor’s series expansion formula