The code doesnt work

Вот код:

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

double X, Y, Z13, t;
int A = 4;
double B = 4.24;

int main() {
cout << "Vvedite X (real): X=";
cin >> X;
cout << endl;
cout << "Vvedite Y (real): Y=";
cin >> Y;
cout << endl;

t = fmod(Y, A);


if (abs(sin(X)) == 0) {
if (t >= 0 and t <= 2) {
Z13=pow(10,1.4)*(pow(cos(X+A),B));
}
else {
Z13 = B - A;
}
}

if (abs(sin(X)) < 0.5 and abs(sin(X) > 0)) {
Z13 = 0.12 * pow(10, 3) * pow(log(X), 2);
}

if (abs(sin(X)) >= 0.5) {

if (Y == 2) {
Z13 = Y - X;
}
else if (Y == 0) {
Z13 = B;
}
else if (Y == 1) {
Z13 = A;
}
else if (Y != 0) {
Z13 = pow(sin(X), 2.1);
}
}

cout << "Z13 = " << Z13 << endl;

return 0;


Если ввести 0 и 9, выводит -nan, не понимаю почему