#include <iostream> #include <cmath> using namespace std; int main() { double x, k, Z; cout << "Вариант 21" << endl; //cout << "Введите x" << endl; cin >> x; k = 1 + pow(x ,2); setlocale(LC_ALL,"Russian"); if (k <= 0) {Z = 2 * cos(3*x)/sin(3*x) ;} else { if (cos (x) == 0) {cout << "Решений нет";} else { Z = 2 * cos(3*x)/sin(3*x) - log(cos(x)) / log (k) ;} ;} cout << "Z = " << Z << endl; return 0; }