term% cat index.txt COS(9.3) COS(9.3)
NAME
cos, sin, atan2, sqrt, norm - integer math functions
SYNOPSIS
int cos(d) int d;
int sin(d) int d;
int atan2(x, y) int x, y;
int norm(x, y, z) int x, y, z;
int sqrt(x) long x;
DESCRIPTION
Cos and Sin return scaled integer approximations to the trigonometric
functions. The argument values are in degrees. The return values are
scaled so that cos(0)=1024. Therefore, to calculate, for example, the
mathematical expression x=x0*cos(d), the multiplication must be scaled:
x=muldiv(x0, cos(d), 1024).
Atan2 returns the approximate arc-tangent of y/x. The return value is
in integral degrees. The approximation is poor; the error may be as
large as two degrees.
Sqrt returns the 16-bit signed integer closest to the square root of
its 32-bit signed argument.
Norm returns the Pythagorean length of the three-vector (x, y, z).
DIAGNOSTICS
Atan2(0, 0) and sqrt(0) return 0. Norm does not protect against over‐
flow.
COS(9.3)