The imaginary unit in Maxima is %i. I think you want expand((a + %i *
b)^2).
declare(b,complex) tells the Maxima simplifier to assume that the
variable 'b' might be complex valued. The simplifier uses such
declarations to decide how to simplify; example:
(%i11) declare(b,complex)$
(%i12) abs(b^2);
(%o12) abs(b)^2
With no declare(a,complex), we have
(%i13) abs(a^2);
(%o13) a^2
Barton
-----maxima-bounces at math.utexas.edu wrote: -----
>To:?maxima at math.utexas.edu
>From:?Folkert?van?Heusden?<folkert at vanheusden.com>
>Sent?by:?maxima-bounces at math.utexas.edu
>Date:?12/05/2009?03:48PM
>Subject:?[Maxima]?expanding?complex?formulas
>
>Hi,
>
>Am?trying?to?expand?formulas?with?complex?values.
>E.g.:
>
>(%i1)?declare(b,complex);
>(%o1)????????????????????????????????done
>(%i2)?(a+b)^2;
>??????????????????????????????????????????2
>(%o2)??????????????????????????????(b?+?a)
>(%i3)?expand(%i2);
>?????????????????????????????????2????????????2
>(%o3)???????????????????????????b??+?2?a?b?+?a
>(%i4)?realpart(expand(%i2));
>??????????????????????2????????????????????????????????2???????2
>(%o4)?????????realpart?(b)?+?2?a?realpart(b)?-?imagpart?(b)?+?a
>(%i5)
>
>But?this?seems?to?be?wrong.
>
>As?far?as?I?know?(a+b.i)^2?would?be?something?like:
>re:?a^2-y^2
>im:?2.a.b.i
>
>What?am?I?doing?wrong?
>
>
>Folkert?van?Heusden
>
>--
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