ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Thu, 14 May 2015 18:32:21 +0200Solve DE with secondary functionhttps://ask.sagemath.org/question/26820/solve-de-with-secondary-function/ I want to solve
$-F''(a) + g(a)( F'(a) - F(a)$
where $g(a)$ is logistic.
My code is
a = var('a')
g(a)= 1 /(1 + e^(-(a)))
F = function('F', a)
de = -diff(F,a, 2) + g(a)*(diff(F,a,1) - F(a))
y = desolve(de, F); y
But I get an error (at the end of the post). If I remove `e(a)` from the `de`-term, I get a solution. What do I have to take into account when I add the second function?
TypeError: no canonical coercion from <class 'sage.symbolic.function_factory.NewSymbolicFunction'> to Symbolic RingWed, 13 May 2015 16:41:29 +0200https://ask.sagemath.org/question/26820/solve-de-with-secondary-function/Comment by rws for <p>I want to solve</p>
<p>$-F''(a) + g(a)( F'(a) - F(a)$</p>
<p>where $g(a)$ is logistic. </p>
<p>My code is</p>
<pre><code>a = var('a')
g(a)= 1 /(1 + e^(-(a)))
F = function('F', a)
de = -diff(F,a, 2) + g(a)*(diff(F,a,1) - F(a))
y = desolve(de, F); y
</code></pre>
<p>But I get an error (at the end of the post). If I remove <code>e(a)</code> from the <code>de</code>-term, I get a solution. What do I have to take into account when I add the second function?</p>
<pre><code>TypeError: no canonical coercion from <class 'sage.symbolic.function_factory.NewSymbolicFunction'> to Symbolic Ring
</code></pre>
https://ask.sagemath.org/question/26820/solve-de-with-secondary-function/?comment=26829#post-id-26829What Sage version? With 6.6 I get `NotImplementedError: Maxima was unable to solve this ODE.
`Thu, 14 May 2015 18:32:21 +0200https://ask.sagemath.org/question/26820/solve-de-with-secondary-function/?comment=26829#post-id-26829