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Re: Limit problem

• To: mathgroup at smc.vnet.net
• Subject: [mg51126] Re: Limit problem
• From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
• Date: Tue, 5 Oct 2004 04:37:16 -0400 (EDT)
• Organization: Uni Leipzig
• References: <cjr9ce$osq$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

and


f[x_] := Sin[12*x^2]/(3*x^2)
Limit[(f[4/10 + h] - f[4/10])/h, h -> 0]

20*Cos[48/25] - (125*Sin[48/25])/12

works fine as to see from:

D[f[x], x] /. x -> 4/10

Don't mix floating point numbers and symbolic computations.

Regards

 Jens

"Mike Zeitzew" <pdop at yahoo.com> schrieb im Newsbeitrag
news:cjr9ce$osq$1 at smc.vnet.net...
> Why is Limit giving me the wrong answer for this simple divided
difference?   I am using 5.0.1.0 /
> XP
>
> In[1]:=
> Clear[f,h,x]
>
> In[2]:=
> f[x_]:=Sin[12*x^2]/(3*x^2)
>
> In[3]:= Limit[(f[0.4 + h] - f[0.4])/h, h -> 0]
>
> Out[3]=
> -&#8734;
>
> In[4]:=
> f'[0.4]
>
> Out[4]=
> -16.631
>