MathGroup Archive 2002

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Sinh[y]/y as y->0?

  • To: mathgroup at
  • Subject: [mg33492] Re: [mg33449] Sinh[y]/y as y->0?
  • From: BobHanlon at
  • Date: Fri, 22 Mar 2002 04:08:58 -0500 (EST)
  • Sender: owner-wri-mathgroup at

In a message dated 3/21/02 11:51:16 AM, siegman at writes:

>A particular calculation produces at an early stage the intermediate result
>   p1 = (Sin[x]/x) + (Sinh[y]/y) ,        (x and y both real)
>and this result then feeds into further expressions in a lengthy symbolic
>When I try to do any numerical evaluations of the final expressions with
>x or y = 0, I get "Indeterminate expression" or "infinity 1/0" error 
>even though the expressions themselves, like the expression above, are
>determinate and finite for those limits.
>Any simple way to make this expression behave as it should under numerical

sa[x_ /; x==0] := 1;
sa[x_?NumericQ] := Sin[x]/x;
sah[x_ /; x==0] := 1;
sah[x_?NumericQ] := Sinh[x]/x;

p1 = (p1 /.
        {Sin[x_]/x_ -> sa[x], Sinh[x_]/x_ -> sah[x]});

Bob Hanlon
Chantilly, VA  USA

  • Prev by Date: Re: Stupid simple question about counting derivatives
  • Next by Date: Re: Getting Symbolic Real and Imag Parts? (Once Again)
  • Previous by thread: Re: Sinh[y]/y as y->0?
  • Next by thread: Re: Sinh[y]/y as y->0?