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  1.  
  2. //Falsi
  3. #include<bits/stdc++.h>
  4.  
  5. using namespace std;
  6.  
  7. double f(double x){
  8.  
  9. return pow(x,3) - 4;
  10. }
  11. int main(){
  12. double x1 = 1.0;
  13. double x2 = 3.0;
  14. double x0;
  15. double f1=f(x1);
  16. double f2=f(x2);
  17. cout<<"Iteration\t"<<"x0\t\t"<<"x1\t\t"<<"x2\t\t"<<"f0\t\t"<<"f1\t\t"<<"f2\n";
  18. if (f1*f2>0){
  19.     cout<<"Invalid! do not bracket any root in this interval."<<endl;
  20.     return 1;
  21. }
  22. for(int i=0;i<3;i++){
  23.      x0 = x1 - (f(x1)*(x2-x1)) / (f(x2)-f(x1));
  24.     double f0 = f(x0);
  25.     cout<<i+1<<"\t"<<x0<<"\t\t\t"<<x1<<"\t\t\t"<<x2<<"\t\t\t"<<f0<<"\t\t\t"<<f1<<"\t\t\t"<<f2<<"\n";
  26.     if (f0==0){
  27.         cout<<"X0 is the root of the equation "<<x0<<endl;
  28.         break;
  29.     }
  30.     if(f1*f2<0){
  31.         x2 = x0;
  32.         f2 = f(x2);
  33.     }
  34.     else{
  35.         x1 = x0;
  36.         f1= f(x1);
  37.     }
  38.     cout<<fixed<<setprecision(5);
  39.  
  40. }
  41. cout<<"After 3 iteration approximate root is :"<<x0<<endl;
  42. return 0;
  43. }
  44.  
Success #stdin #stdout 0s 5252KB
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Standard input is empty
stdout
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Iteration	x0		x1		x2		f0		f1		f2
1	1.23077			1			3			-2.13564			-3			23
2	1.80095			1.00000			1.23077			1.84122			-3.00000			-2.13564
3	1.53696			1.80095			1.23077			-0.36929			1.84122			-2.13564
After 3 iteration approximate root is :1.53696
https://ideone.com/sJHhaX
language:
C++ (gcc 8.3)
created:
8 days ago
visibility:
public

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