# [Maxima] Dot product of complex vectors

Richard Fateman fateman at cs.berkeley.edu
Fri Jun 22 11:32:51 CDT 2007

```Maybe u can do a taylor series expansion  or read about ratwt ratwtlevel
etc.

Basically you might consider letting  q=r+t.  Then compute your expression
as f+a*q+b*q^2+c*q^3+ ....
And then truncate at some power of q.

Maybe drop off the terms after q^1.

Rjf

> -----Original Message-----
> From: maxima-bounces at math.utexas.edu
> [mailto:maxima-bounces at math.utexas.edu] On Behalf Of Daniel Lakeland
> Sent: Friday, June 22, 2007 8:18 AM
> To: maxima at math.utexas.edu
> Subject: Re: [Maxima] Dot product of complex vectors
>
> On Fri, Jun 22, 2007 at 07:23:47AM +0000, Andrew Pinsky wrote:
> > I need to assume that  f(x) >> r(x) + t(x). I.e. that f(x)
> + r(x) + t(x) ~=
> > f(x), and f(x) - r(x) - t(x) ~=f(x).
> >
> > I tried to use subst and ratsubst, but after that r(x) +
> t(x) become zero
> > everywhere.
>
> If r(x) + t(x) never occurs except in conjunction with f(x) then your
> assumption is equivalent to r(x)+t(x) = 0.
>
> You can do ratsubst(f(x),f(x)+r(x)+t(x),expr) and the same for
> f(x)-r(x)-t(x). If this leaves you with no r or t left, perhaps your
> assumption is too strong?
>
>
> --
> Daniel Lakeland
> dlakelan at street-artists.org
> http://www.street-artists.org/~dlakelan
> _______________________________________________
> Maxima mailing list
> Maxima at math.utexas.edu
> http://www.math.utexas.edu/mailman/listinfo/maxima
>
```