double f0(double);
double f1(double);
double f2(double);
double f3(double);
double f4(double);
double f5(double);
double f6(double);
double der_f0(double);
double der_f1(double);
double der_f2(double);
double der_f3(double);
double der_f4(double);
double der_f5(double);
double der_f6(double);
int get_count(void);