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acos, acosf[arc cosine]
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acos,
acosf
[arc cosine]
SYNOPSIS
#include <math.h>
double acos(double x);
float acosf(float x);
DESCRIPTION
acos
computes the inverse cosine (arc cosine)
of the input value. Arguments to acos
must be in the range of -1 to 1.
acosf
is identical to acos,
except that it performs its calculations on floats.
RETURNS
acos
and acosf
return values in radians, in the range
of 0
to
.
If x
is not between -1 and 1, the returned
value is NaN
(not a number) the global variable errno
is set to EDOM,
and a DOMAIN
error
message is sent as standard error output.
You can modify error handling
for these functions using matherr.
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