Post before, but get no answer.

For the function ft = t/(t^2+1) and matrix A. when using subs(ft, t,
A), then the result is based on the element operation. But this is not
I want.

I am hoping to get the result: A * (A^2 + I)^(-1). That is, t is
totally replaced by matrix A and constant becomes indentity matrix.


Any other comments on this?Thanks a lot in advance!
--
Yan ZHANG
http://www.nict.com.sg/zhang/

In article <1103814350.731775.20800@f14g2000cwb.googlegroups.com>,
 <buaanupt@sina.com> wrote:
>Post before, but get no answer.
>
>For the function ft = t/(t^2+1) and matrix A. when using subs(ft, t,
>A), then the result is based on the element operation. But this is not
>I want.
>
>I am hoping to get the result: A * (A^2 + I)^(-1). That is, t is
>totally replaced by matrix A and constant becomes indentity matrix.
>
>
>Any other comments on this?Thanks a lot in advance!
>--
>Yan ZHANG
>http://www.nict.com.sg/zhang/
>


The function FUNM might do what your want.

  -- Cleve Moler
  moler@mathworks.com

Thank you very much for your suggestions.

When ft is the result from mathematical computation. For example,

ft = gt * exp(-2*t);

where gt = mu/(t+mu) with mu as parameter.

In this case, any suggestions?Thank you very much.


-- 

Best Regards

Yan ZHANG
http://www.nict.com.sg/zhang/


"Cleve Moler" <moler@mathworks.com> wrote in message
news:cqf84f$g0a$1@fred.mathworks.com...
> In article <1103814350.731775.20800@f14g2000cwb.googlegroups.com>,
>  <buaanupt@sina.com> wrote:
> >Post before, but get no answer.
> >
> >For the function ft = t/(t^2+1) and matrix A. when using subs(ft, t,
> >A), then the result is based on the element operation. But this is not
> >I want.
> >
> >I am hoping to get the result: A * (A^2 + I)^(-1). That is, t is
> >totally replaced by matrix A and constant becomes indentity matrix.
> >
> >
> >Any other comments on this?Thanks a lot in advance!
> >--
> >Yan ZHANG
> >http://www.nict.com.sg/zhang/
> >
>
>
> The function FUNM might do what your want.
>
>   -- Cleve Moler
>   moler@mathworks.com