.BG
.VE $Header: /usr3/s/current/s/.help/RCS/acos,v 1.2 83/12/30 19:23:46 rab Exp $
.FN acos
.FN asin
.TL
acos asin: Inverse Trigonometric Functions
.CS
acos(x)
asin(x)
.PP
.AG x
numeric structure.  Missing values (NAs) are allowed.
.RT
structure with angles in radians.  For values of `x' outside
the interval [\-1,1], NA is returned and a warning is given.
The range of the result is `0 <= acos(x) <= pi' and `\-pi/2 <= asin(x) <= pi/2'.
.KW basic*
.KW trig
.KW math
.WR
