I have a problem with the CompositeQ function--it only returns my input. So, by the literature:
should return "true".
Instead it returns CompositeQ.
Yes. Great. But...this is what happens to me (question marks are mine...nothing to do with the software).:
Please next time check version when the function was introduced in docs at the bottom of the function's page. It is version 10 for CompositeQ, and your version is 8.
For version 8, you can use something like
CompositeQ = Composition[Not, PrimeQ];
(* True *)