Problem with "is"



On Thu, 1 Oct 2009, deltaquattro at gmail.com wrote:

> I got the following in Maxima:
>
> (%i1)  declare(a,real,b,real);
> (%o1)                                done
> (%i2) c:a+b;
> (%o2)                                b + a
> (%i3) is(c^2>0);
> (%o3)                               unknown

> I know that "is" in Maxima is not very strong, but this is really
> trivial. Is there something I'm doing wrong? Thanks,

That answer's correct, because a and b might both be zero.  Try

is(c^2>=0);

-- 

HTH,

Dan