#include <iostream>
#include <cmath>
#include <cstdlib>
#define EPS 1e-7
using namespace std;
double func(double x)
{
    return x*x-3*x+2;
}
double fb(double x)
{
    return 2*x-3;
}
double bisection(double l,double r)
{
    if(func(l)*func(r)>0)
        cout << "Answer is not in [l,r]\n";
    else
    {
        double mid = l;
        while(r-l>=EPS)
        {
            mid = (l+r)/2;
            if(fabs(func(mid))<=EPS)
                return mid;
            else if(func(mid)*func(l)<0)
                r = mid;
            else
                l = mid;
        }
    }
}
double newton(double x)
{
    while(fabs(func(x)) > EPS)
        x = x - func(x)/fb(x);
    return x;
}
int main()
{
    cout << bisection(-3,1);
    //cout << newton(1.0);
    return 0;
}