# FX_AcosIdx

## Syntax

      #include <nitro/fx/fx_trig.h>

      u16 FX_AcosIdx(fx32 x);

## Arguments

x | `fx32`-format fixed-point decimal.

## Return Values

Arccosine of `x`

## Description

This determines the arccosine of `x`. The results are returned in a `u16` format. The units of the result are equal to 1/65536 of a circle (2 π radians). (Example: A right angle would be 16384.) Internally, a SinCos table is referenced. The argument must take a value between -1 and 1.

## See Also

`FX_Atan, FX_Atan2, FX_AtanIdx, FX_Atan2Idx, FX_AsinIdx`

## Revision History

2007/01/18 Initial version.

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