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   acosf    ( 3 )

функция арккосинуса (arc cosine function)

Имя (Name)

acos, acosf, acosl - arc cosine function

Синопсис (Synopsis)

#include <math.h>

double acos(double x); float acosf(float x); long double acosl(long double x);

Link with -lm.

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

acosf(), acosl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE


Описание (Description)

These functions calculate the arc cosine of x; that is the value
       whose cosine is x.

Возвращаемое значение (Return value)

On success, these functions return the arc cosine of x in
       radians; the return value is in the range [0, pi].

If x is a NaN, a NaN is returned.

If x is +1, +0 is returned.

If x is positive infinity or negative infinity, a domain error occurs, and a NaN is returned.

If x is outside the range [-1, 1], a domain error occurs, and a NaN is returned.


Ошибки (Error)

See math_error(7) for information on how to determine whether an
       error has occurred when calling these functions.

The following errors can occur:

Domain error: x is outside the range [-1, 1] errno is set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.


Атрибуты (Attributes)

For an explanation of the terms used in this section, see
       attributes(7).

┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface Attribute Value │ ├──────────────────────────────────────┼───────────────┼─────────┤ │acos(), acosf(), acosl() │ Thread safety │ MT-Safe │ └──────────────────────────────────────┴───────────────┴─────────┘


Стандарты (Conforming to)

C99, POSIX.1-2001, POSIX.1-2008.

The variant returning double also conforms to SVr4, 4.3BSD, C89.


Смотри также (See also)

asin(3), atan(3), atan2(3), cacos(3), cos(3), sin(3), tan(3)