# arccosine

The inverse of the cosine function, usually abbreviated arccos. It is defined on the restricted domain \([-1,1]\), such that for any real number \(x \in [-1,1]\), \(\arccos(x)=a\) if and only if \(\cos(a)=x\). The principal arcosine takes its values in the interval \([0,\pi]\).

Arccosine may also be abbreviated by acos or cos^{-1}.

- [MLA] “arccosine.”
*Platonic Realms Interactive Mathematics Encyclopedia.*Platonic Realms, 21 Feb 2013. Web. 21 Feb 2013. <http://platonicrealms.com/> - [APA] arccosine (21 Feb 2013). Retrieved 21 Feb 2013 from the
*Platonic Realms Interactive Mathematics Encyclopedia:*http://platonicrealms.com/encyclopedia/arccosine/