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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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.