Найти значения функций

#include <iostream>
#include <conio.h>
#include <iomanip>
#include <math.h>
#include <cmath>
 
using namespace std;
 
int main()
{
    setlocale(LC_ALL, "Russian");
    double x, y, t1, t2;
    double sqrt(double x);
    const double a = 5, b = 4;
    system("cls");
    cout << "x= ";
    cin >> x;
    cout << "y= ";
    cin >> y;
    cout << setprecision(5);
    if (x == 0 || y == 0)
        cout << "Деления на 0" << "\n";
    else
    {
        t1 = 1. / pow(b, 3) * (pow(a, 2) * log(y/x) + 2.(a*x)/y + pow(y,2)/2.* pow(x,2));
        cout << "t1 = " << t1 << "\n";
    }
    if (x == 0 || y == 0)
        cout << "Ошибка!" << "\n";
    else
    {
        t2 = 1. / 2. * sqrt(2.(a)) + 3sin(2) * a * x - 1. / pow(sin,2) * a * x - 1.);
        cout << "t2 = " << t2 << "\n";
    }
    system("pause");
    return 0;
}

#include <iostream>
#include <cmath>
int main()
{
    double a, b, x, y;
    std::cout << "a = "; std::cin >> a;
    std::cout << "b = "; std::cin >> b;
    std::cout << "x = "; std::cin >> x;
    std::cout << "y = "; std::cin >> y;
    if (a*b==0 ||x*y<=0 || pow(sin(a*x),2)==1.0) 
    {
        std::cout<<"Error";
        return 0;
    }
    double t1=a*a*log(y/x)+2*a*x/y+y*y/x/x;
    t1/=b*b*b;
    double t2=pow(sin(a*x),2);
    t2=1.0/2/sqrt(2.0)/a+(3*t2-1)/(t2-1);
    std::cout << "t1 = " << t1 << "; t2 = " << t2;
    return 0;
}