On 4/11/2012 11:58 AM, Holger Schulz wrote:
> I'm not quite sue if I understand your question. English is not my native language.
>
> sqrt(q) is real for non-negative values of q.
>
> But, what about maxima knowing if a solution is real? I just want solutions with an imnaginary pert not to be printed. Is that possible?
>
> Thanks.
>
> hs
>
> Am 2012-04-11 um 20:47 schrieb Richard Fateman:
>
>> How do you know if a solution is real? Is sqrt(q) real?
Maxima deals with symbols as well as numbers.
Here's an equation:
sin(y)=x
Solve for y. y=asin(x).
Is this real? we know that if x is real and abs(x)>1 that
this is a complex solution. But say we don't know ANYTHING
about x, in general. Maxima is quite capable of continuing
to compute with asin(x) regardless. So the determination of
whether a SYMBOLIC expression is real or complex is not
possible in general.
as another example..
%i*sin(%i*x)
is real if x is real...