To Find the Roots of an Equation Using the Regula Falsi Method - C Data Structure

C examples for Data Structure:Algorithm

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Description

To Find the Roots of an Equation Using the Regula Falsi Method

Demo Code

#include<stdio.h>
#include<math.h>

#define EPS 0.00001//from  w  w  w. ja  v  a2s . co  m
#define f(x) 3*x*x*x + 5*x*x + 4*cos(x) - 2*exp(x)

void falsePosition();

void main()
{
  printf("\nEquation :    3*x*x*x + 5*x*x + 4*cos(x) - 2*exp(x) = 0");
  falsePosition();
}

void falsePosition(){
  float fun1, fun2, fun3;
  float x1, x2, x3;
  int iterations =7;
  int i;
  x2 = 0.0;
  do {
    fun2 = f(x2);
    if(fun2 > 0) {
      break;
    }
    else {
      x2 = x2 + 0.1;
    }
  } while(1);
  x1 = x2 - 0.1;
  fun1 = f(x1);
  printf("\nIteration No.\t\tx\t\tF(x)\n");
  i = 0;
  while (i < iterations) {
    x3 = x1 - ((x2 - x1) / (fun2 - fun1)) * fun1;
    fun3 = f(x3);
    if(fun1 * fun3 > 0) {
      x2 = x3;
      fun2 = fun3;
    }
    else {
      x1 = x3;
      fun1 = fun3;
    }
    printf("\n%d\t\t\t%f\t%f\n", i+1, x3, fun3);
    if (fabs(fun3) <= EPS)
      break;
    i++;
  }
  printf("\n\nTotal No. of Iterations:  %d", i+1);
  printf("\nRoot, x = %8.6f \n", x3);
}

Result


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