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# acos

From cppreference.com
< c‎ | numeric‎ | math

Defined in header `<math.h>` |  |
float acosf( float arg ); |  | (since C99)
double acos( double arg ); |  |
long double acosl( long double arg ); |  | (since C99)

Computes arc cosine of `arg`

### [edit] Parameters

arg | - | floating point value

### [edit] Return value

Arc cosine of `arg` in radians in the range of `[0; π]` radians.

Domain error occurs if `arg` is outside the range `[-1.0; 1.0]`. NAN is returned in that case.

### [edit] See also

asin | computes arc sine (arcsin(x)) (function) [edit]
atan | computes arc tangent (arctan(x)) (function) [edit]
atan2 | arc tangent, using signs to determine quadrants (function) [edit]
cos | computes cosine (cos(x)) (function) [edit]
C++ documentation for acos

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