Re: Series[] command
- To: mathgroup at smc.vnet.net
- Subject: [mg55951] Re: [mg55939] Series[] command
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Tue, 12 Apr 2005 05:26:00 -0400 (EDT)
- Reply-to: hanlonr at cox.net
- Sender: owner-wri-mathgroup at wolfram.com
They are equal
Series[a*b,{a,ma,2},{b,mb,2}]//Normal
a (b-mb)+(a-ma) mb+ma mb
%//Simplify
a b
ma*mb+ma(b-mb)+mb(a-ma)+(a-ma)(b-mb)//Simplify
a b
Bob Hanlon
>
> From: "Kris Preacher" <preacher at unc.edu>
To: mathgroup at smc.vnet.net
> Date: 2005/04/10 Sun PM 11:07:18 EDT
> To: mathgroup at smc.vnet.net
> Subject: [mg55951] [mg55939] Series[] command
>
> Hi all,
>
> I need to obtain the second-order Taylor series expansion of a*b around
the
> points ma and mb. I thought Mathematica's Series[] command would do the
> trick, but no. The correct answer is:
>
> ma*mb + ma(b-mb) + mb(a-ma) + (a-ma)(b-mb)
>
> Mathematica gives:
>
> b(a-ma) + ma(b-mb) + ma*mb
>
> Whaddup??
>
> Thanks,
> Kris Preacher
> UNC
>
>
>