Here's the question you clicked on:
JenniferSmart1
\[cos(cos^{-1}1.2)\] this is outside the boundary \[-1\le x \le 1\]
oh it's just undefined....nevermind LOL
:O http://www.wolframalpha.com/input/?i=cos+%28arccos+1.2%29
wolfram is wrong
even i think so...it should be undefined.