Re: Differential Equations in Octave - can it solve them?

On Sat, Nov 21, 2020 at 7:09 PM <[email protected]> wrote:

>     I want an analytic solution. I’d like Octave’s answer for  was .
> Using symbolic solver for ODEs, the result/answer I get it is shown below.
>
>
>
>      I don’t know how to solve it.
>
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>

Please always copy in the main help list so everyone can help and so that
the community can learn from our messages. Also, please write your response
below the previous message when responding to this list, and whenever
possible, please copy in the output of the command line instead of posting
a screenshot.

It's helpful to read the documentation for diff
<https://octave.sourceforge.io/symbolic/function/@sym/diff.html> and for
dsolve <https://octave.sourceforge.io/symbolic/function/@sym/dsolve.html>.

diff(S,S) is not a differential, it is dS/dS=1. You can see this in your
code; no term such as dS appears.

If you know the answer, why are you asking Octave to solve it? These
integrals can be done analytically by realizing that d/dx ( ln( f(x) ) ) =
df/dx / f(x) . I would recommend posting mathematical questions on
math.stackexchange.com/, or consulting the thermodynamics textbook where
you found this equation.