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### substitute a matrix in a non-poly function

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```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.

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

```
 0
Reply buaanupt (78) 12/23/2004 3:05:50 PM

See related articles to this posting

```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.
>
>
>--
>Yan ZHANG
>http://www.nict.com.sg/zhang/
>

The function FUNM might do what your want.

-- Cleve Moler
moler@mathworks.com
```
 0
Reply moler1 (157) 12/23/2004 8:00:15 PM

```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...
>  <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.
> >
> >
> >--
> >Yan ZHANG
> >http://www.nict.com.sg/zhang/
> >
>
>
> The function FUNM might do what your want.
>
>   -- Cleve Moler
>   moler@mathworks.com

```
 0
Reply buaanupt (78) 12/24/2004 1:31:43 AM

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