I have a function defined as
a[x_]:=If[x==0,const,f[x]]
where $f(0)\neq const$.
How do I evaluate $a(x)$ such that I just get $f(x)$ without having to put in a specific x value greater than 0? I've tried things like $/;$, Assumptions and Assuming, but haven't been able to do it. This seems like it should be a simple thing, any ideas?