How to enter a periodic function in Sagemath?

edit

I tried this sample code which is working fine:

sage: def periodic_function(x):
....:     result1 = sin(x/2)
....:     result2 = tan(x/2)
....:     result3 = cos(x/4)
....:     return result1, result2, result3
....:

sage: print(periodic_function(pi))
(1, Infinity, 1/2*sqrt(2))