ASKSAGE: Sage Q&A Forum - Individual question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 08 Oct 2012 07:19:20 -0500Roots in a solutionhttp://ask.sagemath.org/question/9402/roots-in-a-solution/When I solve the equations I obtained from the code in [this question](http://ask.sagemath.org/question/1848/eliminating-fractions-and-roots-from-equations), I get a number of solutions. Most of them complex numbers, whereas the single real solution simply prints as `r1` when first executing the code, as `r2` next, and so on. So I gather that this is some root which Maxima or whoever is doing the solving cannot reduce to radicals.
So far, so good, but I'd still like to be able to get an idea of what that thing represents. Saving my solutions to a list of dictionaries, I've been able to isolate that value, but I can't seem to find any reasonable methods to obtain further details. In particular, `r.n()` tells me that it
TypeError: cannot evaluate symbolic expression numerically
So what can I do? how can I figure out what this thing actually represents? I believe that it might be some root of a polynomial which still contains one variable from my equation. But how can I obtain that polynomial?Mon, 08 Oct 2012 06:19:15 -0500http://ask.sagemath.org/question/9402/roots-in-a-solution/Answer by kcrisman for <p>When I solve the equations I obtained from the code in <a href="http://ask.sagemath.org/question/1848/eliminating-fractions-and-roots-from-equations">this question</a>, I get a number of solutions. Most of them complex numbers, whereas the single real solution simply prints as <code>r1</code> when first executing the code, as <code>r2</code> next, and so on. So I gather that this is some root which Maxima or whoever is doing the solving cannot reduce to radicals.</p>
<p>So far, so good, but I'd still like to be able to get an idea of what that thing represents. Saving my solutions to a list of dictionaries, I've been able to isolate that value, but I can't seem to find any reasonable methods to obtain further details. In particular, <code>r.n()</code> tells me that it</p>
<pre><code>TypeError: cannot evaluate symbolic expression numerically
</code></pre>
<p>So what can I do? how can I figure out what this thing actually represents? I believe that it might be some root of a polynomial which still contains one variable from my equation. But how can I obtain that polynomial?</p>
http://ask.sagemath.org/question/9402/roots-in-a-solution/?answer=14118#post-id-14118If you check out the [documentation for solve](http://www.sagemath.org/doc/reference/sage/symbolic/expression.html#sage.symbolic.expression.Expression.solve), you'll see that
> In some cases there may be infinitely many solutions indexed by a dummy variable. If it begins with z, it is implicitly assumed to be an integer, a real if with r, and so on:Mon, 08 Oct 2012 07:19:20 -0500http://ask.sagemath.org/question/9402/roots-in-a-solution/?answer=14118#post-id-14118