Funzioni per la matematica:
double acos(double x);
double asin(double x);
double atan(double x);
double atan2(doubly y, double x);
double cos(double x);
double cosh(double x);
double sin(double x);
double sinh(double x);
double tan(double x);
double tanh(double x);
double exp(double x);
double frexp(double x, int *exponent);
double ldexp(double x, int exponent);
double log(double x);
double log10(double x);
double modf(double x, double *integer);
double pow(double x, double y);
double sqrt(double x);
double ceil(double x);
double fabs(double x);
double floor(double x);
double fmod(double x, double y);