Bill Allombert on Thu, 30 Oct 2003 12:10:10 +0100

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Re: new user

On Wed, Oct 29, 2003 at 09:03:07PM +0100, Marko Riedel wrote:
> Hi folks,
> I downloaded and compiled PARI yesterday and I'm quit excited about
> learning how to use GP and program with libpari.
> I have two very basic questions:
> - how do I invert a matrix of rational functions with GP or using
>   libpari?

Under GP it is easy:
? M=[a,b;c,d];
? M^-1
%2 =
[d/(d*a - c*b) -b/(d*a - c*b)]

[-c/(d*a - c*b) a/(d*a - c*b)]

Don't expect good performances if there are lots of variables, though.

> - does GP or libpari have a feature for symbolic integration or
>   differentiation?

Not really. Only when both data and result are rational functions. See
intformal() and deriv().