Category Archives: Bisection Method

C code for bisection method

The Bisection Method is a numerical method for estimating the roots of a polynomial f(x). It is one of the simplest and most reliable but it is not the fastest method.
Problem: Here we have to find root for the polynomial x^3+x^2-1
Solution in C:

Algorithm:

  1. Start
  2. Read a1, b1, TOL
    *Here a1 and b1 are initial guesses
    TOL is the absolute error or tolerance i.e. the desired degree of accuracy*
  3. Compute: f1 = f(a1) and f3 = f(b1)
  4. If (f1*f3) > 0, then display initial guesses are wrong and goto step 11
    Otherwise continue.
  5. root = (a1 + b1)/2
  6. If [ (a1 – b1)/root ] < TOL , then display root and goto step 11
    * Here [ ] refers to the modulus sign. *
    or f(root)=0 then display root
  7. Else, f2 = f(root)
  8. If (f1*f2) < 0, then b1=root
  9. Else if (f2*f3)<0 then a1=root
  10. else goto step 5
    *Now the loop continues with new values.*
  11. Stop

Output:

2014-11-09 03_03_31-

Another Problem Solving Code:
Problem:
Here we have to find root for the polynomial x^3+x^2-1 upto 4D

Output:2014-11-27 12_22_54-