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.
Thus, to calculate 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.
Sqrt returns the 16-bit signed integer closest to the square
root of its 32-bit signed argument.
Norm returns the Euclidean length of the three-vector (x, y,
z).
DIAGNOSTICS
Sqrt returns 0 for negative arguments; and atan2(0,0)==0.
Norm does not protect against overflow.
BUGS
Atan2 may be off by as much as two degrees.