
Functions HITECH C ACOS
From HITECH C for CP/M Fan WIKI(EN)
ACOS, ASIN, ATAN, ATAN2
SYNOPSIS
#include <math.h> double acos(double f) double asin(double f) double atan(double f) double atan2(double x, double y)
DESCRIPTION
These functions are the converse of the trignometric functions cos, sin and tan. Acos and asin are undefined for arguments whose absolute value is greater than 1.0. The returned value is in radians, and always in the range pi/2 to +pi/2, except for cos(), which returns a value in the range 0 to pi. Atan2() returns the inverse tan of x/y but uses the signs of its arguments to return a value in the range pi to +pi.
SEE ALSO
sin, cos, tan