expression evaluation



Hi guys,

  Could you suggest how to overcome non-proper evaluation. And generally, is maxima capable to simplify such expression?

  The expression: cos( %pi n x) at point x=1/2. That should be 0.

Here the trace:

-------------------------------------------------------
(%i1) declare(n, integer);
(%o1)                                done
(%i2) cos( %pi * n * x);
(%o2)                            cos(%pi n x)
(%i3) ev( %, x=1/2,pred, expand, simp,eval );
                                      %pi n
(%o3)                             cos(-----)
                                        2
(%i4) 
------------------------------------------------------

At point x=1 everything calculates:

-------------------------------------------------------
(%i1) declare(n, integer);
(%o1)                                done
(%i2) cos( %pi * n * x);
(%o2)                            cos(%pi n x)
(%i3) ev( %, x=1,pred, expand, simp,eval );          
                                         n
(%o3)                               (- 1)
(%i4) 
-------------------------------------------------------

--
BR, Ruslan Mullakhmetov