#include <iostream>
#include <cmath>
#include <cstdio>
#define M_PI 3.14159265358979323846

using namespace std;

double f(double x){
    return x*x-4;
}

double g(double x){
    return sin(2*x);
}

//double f(double x){
//    return -x*x/50.0;
//}

//double g(double x){
//    return 1+x*x/100.0-x/200.0;
//}

double pole(double a, double b, double h){
    double S = 0;
    double x0 = a;
    double x1 = x0+h;

    while(x0<=b){
        S+=(g(x0)-f(x0)+g(x1)-f(x1))*h/20.0;
        x0 = x1;
        x1+=h;
    }
    return S;
}

int retC(int &a, int &b){
    int i,j;
    for(i=0; g(i)-f(i)<26; i++);
    i+=100;

    for(j=0; g(j)-f(j)<100; j++);
    j+=26;

    if(i<j){
        a= 26;
        b= 100;
        return i;
    }
    else{
        a=100;
        b=26;
        return j;
    }
}

void wypisz(){
    int a,b;
    int c = retC(a,b);

    cout << "A = (" << c << ", " << g(c-b) << ") "<<endl;
    cout << "B = (" << c << ", " << g(c-b)-a << ") "<<endl;
    cout << "C = (" << c-b << ", " << g(c-b)-a << ") "<<endl;
    cout << "D = (" << c-b << ", " << g(c-b) << ") "<<endl;

    cout << "wartosci funkcji: " <<endl;
    cout <<f(58) << " " <<g(58) <<endl;


}


double bisekcjaF(double a, double b, double d){
    double sr;
    while(fabs(a-b)>d){
        sr= (a+b)/2;
        if(f(sr)*f(b)>0){
            b=sr;
        }
        else{
            a=sr;
        }
    }
    return sr;
}


double bisekcjaG(double a, double b, double d){
    double sr;
    while(fabs(a-b)>d){
        sr= (a+b)/2;
        if(g(sr)*g(b)>0){
            b=sr;
        }
        else{
            a=sr;
        }
    }
    return sr;
}




int main()
{

    //zad.1.
//    cout << pole(0,10,0.01);
//    wypisz();

    //zad.2. bisekcja
   // cout << bisekcjaF(1,5,0.01);

    cout << bisekcjaG(5,10,0.0000001) <<endl;
    cout << 2* M_PI <<endl;

    return 0;
}