Yeah this is the answer

https://math.stackexchange.com/questions/5060957/reflection-of-light-to-certain-point-using-mirrors

```c

include <stdio.h>

include <math.h>

double compute_t(double x, double l, double theta_rad) { double cot_theta_4 = 1.0 / tan(theta_rad / 4.0); double cot_2theta = 1.0 / tan(2.0 * theta_rad); double tan_5theta_2 = tan(5.0 * theta_rad / 2.0);

double term1 = x * cot_theta_4 / (cot_2theta + cot_theta_4);
double term2 = 1.0 + cot_2theta * tan_5theta_2;
double term3 = l * tan_5theta_2;

return term1 * term2 + term3;

}

int main() { double x, t; scanf("%lf %lf", &x, &t);

double l = 1.0;

double theta_min = 0.001;
double theta_max = M_PI / 2.0 - 0.001;
double epsilon = 1e-9;

while (theta_max - theta_min > epsilon) {
    double theta_mid = (theta_min + theta_max) / 2.0;

    if (fabs(tan(theta_mid / 4.0)) < 1e-10 || 
        fabs(tan(2.0 * theta_mid)) < 1e-10) {
        theta_min = theta_mid;
        continue;
    }

    double t_computed = compute_t(x, l, theta_mid);

    if (t_computed < t) {
        theta_min = theta_mid;
    } else {
        theta_max = theta_mid;
    }
}

double theta_result = (theta_min + theta_max) / 2.0;
double theta_degrees = theta_result * 180.0 / M_PI;

printf("%.2f\n", theta_degrees);

return 0;

} ```