Question 1152524


Some people distinguish between the inverse cosine function (which has the range restricted so there is only one value) and arccos not having the range restricted so it is multivalued, but that doesn't seem to be your problem.

{{{cos^-1(x) = arccos( x)}}}


{{{arcos (sqrt(2)/2)=pi/4}}}

{{{cos^-1(sqrt(2)/2)=pi/4}}}