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  1. #include <stdio.h>
  2. #include <math.h>
  3.  
  4. double f(double x) {
  5.     double coe[] = {1, 0, -4, -9};
  6.     double result = coe[0];
  7.     for (int i = 1; i < 4; i++)
  8.         result = result * x + coe[i];
  9.     return result;
  10. }
  11.  
  12. int main() {
  13.     double x1, x2, x3, f1, f2, f3;
  14.     int step = 1;
  15.     printf("Enter the value of x1: ");
  16.     scanf("%lf", &x1);
  17.     printf("Enter the value of x2: ");
  18.     scanf("%lf", &x2);
  19.  
  20.     printf("\n   Iteration\t      x1\t        x2\t        x3\t      f(x1)\t      f(x2)\n");
  21.     printf("   --------------------------------------------------------------------------\n");
  22.  
  23.     f1 = f(x1);
  24.     f2 = f(x2);
  25.  
  26.     do {
  27.         x3 = (f2 * x1 - f1 * x2) / (f2 - f1);
  28.         f3 = f(x3);
  29.         printf("%8d\t%12.6lf\t%10.6lf\t%10.6lf\t%10.6lf\t%10.6lf\n", step, x1, x2, x3, f1, f2);
  30.         if (fabs(f3) < 0.00001)
  31.             break;
  32.         x1 = x2;
  33.         f1 = f2;
  34.         x2 = x3;
  35.         f2 = f3;
  36.         step++;
  37.     } while (step <= 8);
  38.  
  39.     printf("   --------------------------------------------------------------------------\n");
  40.     printf("\n   Approximate root = %.6lf\n", x3);
  41.     return 0;
  42. }
  43.  
Success #stdin #stdout 0.01s 5312KB
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stdin
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4
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stdout
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Enter the value of x1: Enter the value of x2: 
   Iteration	      x1	        x2	        x3	      f(x1)	      f(x2)
   --------------------------------------------------------------------------
       1	    4.000000	  2.000000	  2.375000	 39.000000	 -9.000000
       2	    2.000000	  2.375000	  2.866165	 -9.000000	 -5.103516
       3	    2.375000	  2.866165	  2.681284	 -5.103516	  3.080613
       4	    2.866165	  2.681284	  2.704785	  3.080613	 -0.448618
       5	    2.681284	  2.704785	  2.706548	 -0.448618	 -0.031298
       6	    2.704785	  2.706548	  2.706528	 -0.031298	  0.000360
   --------------------------------------------------------------------------

   Approximate root = 2.706528
https://ideone.com/0zUNXR
language:
C++ (gcc 8.3)
created:
7 days ago
visibility:
public

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