Laba 3

#include <iostream>
#include <cmath>

using namespace std;

int main()
  {
    setlocale(0,"");

    int N;
    do
      {
        cout << "Ââåäèòå N (N >= 1):\n";
        cin >> N;
      }
    while (N < 1);

    double x;
    do
      {
        cout << "Ââåäèòå x (-1 < x < 1):\n";
        cin >> x;
      }
    while (abs(x) > 1);

    double E;
    do
      {
        cout << "Ââåäèòå E (E > 0): \n";
        cin >> E;
      }
    while (E <= 0);

    double t = (-2)*x;
    double sum = 1;
    int i = 1;
    for (; i <= N; i++)
      {
        sum += t;
        t *= (-1)*x*(i+2)/(i+1);
      }
    cout << "Ñóììà N ñëàãàåìûõ ðàâíà " << sum;

    i = 1;
    t = (-2)*x;
    sum = 1;
    for (; abs(t) > E; i++)
      {
        sum += t;
        t *= (-1)*x*(i+2)/(i+1);
      }
    cout << "\nÑóììà ñëàãàåìûõ, êîòîðûå ïî ìîäóëþ áîëüøå E ðàâíà " << sum;
    cout << "\nÊîëè÷åñòâî ñëàãàåìûõ, êîòîðûå ïî ìîäóëþ áîëüøå E ðàâíà " << i;

    for  (; abs(t) > E/10; i++)
      {
        sum += t;
        t *= (-1)*x*(i+2)/(i+1);
      }
    cout << "\nÑóììà ñëàãàåìûõ, êîòîðûå ïî ìîäóëþ áîëüøå E/10 ðàâíà " << sum;
    cout << "\nÊîëè÷åñòâî ñëàãàåìûõ, êîòîðûå ïî ìîäóëþ áîëüøå E/10 ðàâíà " << i;
    cout << "\nÒî÷íîå çíà÷åíèå 1/(1+"<< x <<")^2 = " << (1/((1+x)*(1+x)));

    system("PAUSE");
    return 0;
  }