Уравнение x = A*cos(x)

//---------------------------------------------------------------------------
#include <iostream.h>
#include <math.h>
#include <stdio.h>
//---------------------------------------------------------------------------
void main()
{      double y,x,a,eps,alpha; int k,n;
 
cout << "Set x=";    cin>>x;       getchar();
y=(exp(x)+exp(-x))/2;    //chx
//вывод точного результата
cout <<"\n\t\tFor function y=chx   at x="<< x << " exact value y="<<y <<"\n\n";
 
cout << "Set value eps (End - 0).   eps=";    cin>>eps;       getchar();
//cycle
while(eps!=0)
{  cout << "\nAt  eps=" <<eps<<endl;
   for (a=x*x/2,y=1,n=1,k=1;
        fabs(a)>=eps&&n<1000;
        n++,k++,y+=a,alpha=(x*x)/(2*k *(2*k-1)),a*=alpha)
{      //вывод результатов
        cout << "The approached value y="<< y
        << "\t\tIt is summarized " << n << " members of line"<<endl;
};
cout << "\nSet value eps (End - 0).   eps=";    cin>>eps;       getchar();
}
cout << "\nProgram over! Press Enter.\n";
getchar();
}
//---------------------------------------------------------------------------

#include <cmath>
#include <iostream>
 
using namespace std;
 
int main() {
    const double pi = acos(-1.0);
    double x=0.0, x0, A, eps;
    cout << "A = ";
    cin >> A;
    cout << "eps = ";
    cin >> eps;
    do {
        x0 = x;
        x = A*cos(x0);
    } while (abs(x-x0) > eps);
    cout << "x = " << x << endl;
    system("pause");
    return 0;
}
}

#include <cmath>
#include <iostream>
 
using namespace std;
 
int main() {
    const double pi = acos(-1.0);
    double x=0.0, x0, A, eps;
    cout << "A = ";
    cin >> A;
    cout << "eps = ";
    cin >> eps;
    do {
        x0 = x;
        x = A*exp(-x0);
    } while (abs(x-x0) > eps);
    cout << "x = " << x << endl;
    system("pause");
    return 0;
}

#include <cmath>
#include <iostream>
using namespace std;
int main() {
   double x = 0.47, x0, A, eps = 0.00001;
    cout << "A = ";
    cin >> A;
    do {
        x0 = x;
       x  =  A * exp(-x0);
 
    } while ((x-x0) < 1.0);
    cout << "x = " << x << endl;
    system("pause");
    return 0;
}

#include <cmath>
#include <iostream>
 
using namespace std;
 
int main() {
     double x=0.0, x0, A, eps;
    cout << "eps = ";
    cin >> eps;
    cout << "A = ";
    cin >> A;
    if (fabs (A) >= 3)
    {
    cout << "No solutions " << endl;
}
    else
    {
    do {
        x0 = x;
        x = A*exp(-x0);
    } while (fabs(x-x0) > eps);
    cout << "x = " << x << endl;
}
    system("pause");
    return 0;
}

#include <cmath>
#include <iostream>
 
using namespace std;
 
int main() {
     double x=0.0, x0, A, eps;
    cout << "eps = ";
    cin >> eps;
    cout << "A = ";
    cin >> A;
    if  (A >= 3) 
    {
    cout << "No solutions " << endl;
}
    else
    {
    do {
        x0 = x;
        x = A*exp(-x0);
    } while (fabs(x-x0) > eps);
    cout << "x = " << x << endl;
}
    system("pause");
    return 0;
}

#include <cmath>
#include <iostream>
#include <limits>
 
using namespace std;
 
int main() {
    setlocale(LC_ALL, "Rus");
    double inf = numeric_limits<double>::infinity();
    double x=0.0, x0, A, eps;
    int k=0, maxIterations = 10000;
    cout << "A = ";
    cin >> A;
    cout << "eps = ";
    cin >> eps;
    do {
        ++k;
        x0 = x;
        x = A*exp(-x0);
    } while ((fabs(x-x0) > eps) && (k < maxIterations));
    if (k == maxIterations)
        cout << "Метод расходится" << endl;
    else
        if (fabs(x) == inf)
            cout << "Нет решений" << endl;
        else
            cout << "x = " << x << endl;
    system("pause");
    return 0;
}

#include <cmath>
#include <iostream>
using namespace std;
 
double A;
double g(double x)
{
    return A*cos(x);
}
 
double f(double x)
{
    return x - g(x);
}
 
int main()
{
    double x;
    double eps;
    cout<<"Enter initial value of A : ";cin>>A;
    cout<<"Enter initial value of x : ";cin>>x;
    cout<<"Enter calculetions error : ";cin>>eps;
    while(eps < fabs(f(x)))
    {
        system("cls");
        cout<<"x   = "<<(x = g(x))<<endl;
        cout<<"err = "<<f(x)<<endl;
    }
    cout<<"\tResults"<<endl;
    cout<<"x        = "<<x<<endl;
    cout<<"A*cos(x) = "<<g(x)<<endl;
    system("pause");
    return 0;
}

#include <cmath>
#include <iostream>
using namespace std;
 
double A;
double g(double x)
{
    return /*A*cos(x)*/A*exp(-x);
}
 
double f(double x)
{
    return x - g(x);
}
 
int main()
{
    double x;
    double eps;
    cout<<"Enter initial value of A : ";cin>>A;
    cout<<"Enter initial value of x : ";cin>>x;
    cout<<"Enter calculetions error : ";cin>>eps;
    while(eps < fabs(f(x)))
    {
        system("cls");
        cout<<"x   = "<<(x = g(x))<<endl;
        cout<<"err = "<<f(x)<<endl;
    }
    cout<<"\tResults"<<endl;
    cout<<"x        = "<<x<<endl;
    //cout<<"A*cos(x) = "<<g(x)<<endl;
    cout<<"A*exp(-x) = "<<g(x)<<endl;
    system("pause");
    return 0;
}