Re: infuriating Series[] question

• To: mathgroup at smc.vnet.net
• Subject: [mg17265] Re: [mg17226] infuriating Series[] question
• From: "Tomas Garza" <tgarza at mail.internet.com.mx>
• Date: Fri, 30 Apr 1999 02:34:47 -0400
• Sender: owner-wri-mathgroup at wolfram.com

```Peter Jay Salzman [psalzman at landau.ucdavis.edu] wrote:

>I'm trying to develop very high order difference equations, and
> want to use
> Mathematica to save me from calculating tons of quantities like 5^10 / 7!
>
> If I define:
>    g[x_] := Series[ f[x], {x,0,10} ]
>
> And try to compute stuff like:
>
>    g[5*h] or g[10*h]
>
> It gives me the right answer, but i get terms like
>
>    f'''''[0] * (5 x)^(10) / 10!
>
> The whole point in using Mathematica is so that I don't have to
> calculate things
> which look like 5^10 / 10!   (that's factorial, of course, not me being
> emphatic).
>
> Even when I try things like // Simplify or // FullSimplify,
> Mathematica refuses to
> simplify these rational coefficients.   One thing I've learned is
> that Mathematica
> can do anything -- but figuring out how to do the something is often
> completely not obvious to a nominal user like me.
>
> Can someone tell me the secret here?

Hi, Pete:

Yes, indeed! Just use the function N:

In[1]:=
N[5^10/10!]
Out[1]=
2.69114

Good luck,

Tomas Garza
Mexico City

```

• Prev by Date: Re: Mathematica in Chemistry
• Next by Date: Re: assignment of matrix elements
• Previous by thread: Re: infuriating Series[] question
• Next by thread: Re: infuriating Series[] question