#include <math.h> /* include the math library */
double floor(double x); /* chop off fractional part of x */
double ceil (double x); /* raise x to next largest integer */
double fabs(double x); /* compute the absolute value of x */
double sqrt(double x); /* compute square roots */
double exp(double x); /* compute e?x */
double log(double x); /* compute the base-e logarithm */
double log10(double x); /* compute the base-10 logarithm */
double pow(double x, double y); /* compute x?y */
}