Create the OSCILLATE function.

proc fcmp outlib=sasuser.funcs.curves;
   function oscillate(x,amplitude,frequency);
         if amplitude le 0 then amp=1; else amp=amplitude;
	      if frequency le 0 then freq=1; else freq=frequency;
         y=sin(freq*x)*constant("e")**(-amp*x); 
         return (y);
  endsub;