NAME
cos(), cosf(), cosl(), cosw(), cosq() — cosine functions
SYNOPSIS
#include <math.h>
double cos(double x);
float cosf(float x);
IA-64 ONLY:
long double cosl(long double x);
extended cosw(extended x);
quad cosq(quad x);
DESCRIPTION
cos()
returns the cosine of
x
(x
specified in radians).
cos()
may lose accuracy when
x
is far from zero.
cosf()
is a
float
version of
cos();
it takes a
float
argument and returns a
float
result.
IA-64 ONLY:
cosl()
is a
long double
version of
cos();
it takes a
long double
argument and returns a
long double
result.
cosw()
is an
extended
version of
cos();
it takes an
extended
argument and returns an
extended
result.
cosq()
is equivalent to
cosl()
on HP-UX systems.
USAGE
To use these functions compile either with the default
-Ae
option or with the
-Aa
and the
-D_HPUX_SOURCE
options.
To use (for IA-64 systems)
cosw()
or
cosq(),
compile also with the
-fpwidetypes
option.
To use any of these functions, make sure your program includes
<math.h>,
and link in the math library by specifying
-lm
on the compiler or linker command line.
For more information, see the
HP-UX Floating-Point Guide.
PA-RISC ONLY:
Millicode versions of the
cos()
and
cosf()
functions are available.
Millicode versions of math library functions are usually
faster than their counterparts in the standard library.
To use these versions, compile your program with the
+Olibcalls
or the
+Oaggressive
optimization option.
For special cases, the millicode versions return the same values as
their standard library counterparts (see the
RETURN VALUE
section).
RETURN VALUE
cos(±0)
returns 1.
If
x
is ±INFINITY,
cos()
returns NaN and raises the invalid exception.
If
x
is NaN,
cos()
returns NaN.
When it raises no other exception,
whether
cos()
raises the
inexact exception is unspecified.
ERRORS
No errors are defined.
STANDARDS CONFORMANCE
cos()
: SVID3, XPG4.2, ANSI C, ISO/IEC C99
(including Annex F, ``IEC 60559 floating-point arithmetic'')
cosf(),
cosl()
: ISO/IEC C99 (including Annex F, ``IEC 60559 floating-point arithmetic'')
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