How do you evaluate $arccos{cos(pi/3)}$ ?

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Answer 1 · 2016-06-25T02:09:22

$pi/3$

cos and arc cos are inverse operators.

For any inverse operator couple $[O, O^(-1)]$ ,

$O(O^(-1)x) = x and O^(-1)(Oy)=y$ .

Here, $arc cos (cos (pi/3))=pi/3$

Despite $cos(pi/3)=1/2=cos(-pi/3)$ ,.

$arc cos(cos(-pi/3))=-pi/3$ , and not $pi/3.$ .

How do you evaluate arccos{cos(pi/3)} arccos{cos(pi/3)}?