Nope. Using `sympy` through `sage` :
``` sage: reset() sage: t=var("t") sage: B=function("B") sage: Eq=-B(t)^2-B(t).diff(t)+1==0 sage: import sympy sage: Sol=sympy.dsolve(*map(sympy.sympify, (Eq, B(t))))._sage_() ; Sol B(t) == -1/tanh(C1 - t) sage: C1=var("C1") sage: foo(t)=Sol.rhs() sage: bool(Eq.substitute_function(B, foo)) True sage: bar(t)=tanh(C1-t) sage: bool(Eq.substitute_function(B, bar)) False ``` HTH, Le lundi 4 avril 2022 à 00:39:41 UTC+2, kang.mat...@gmail.com a écrit : > There is an issue in the sympy.dsolve module. When I was trying to solve > the ode: -B(t)^2 - B'(t) +1 =0. The proper result should be tanh(C_1 - t), > while the given result is the 1/tanh(C_1 - t). > > I can help to solve this issue as a GSOC project if provided the > permission from the community. I often use the sympy package, and I love it > as it is a competitive alternative to the Wolfram Mathematica. > > And I am now a master's student at the Mathematical Institute, Oxford > University. Before coming here, I possess a computer science undergraduate > degree. Here is my Linkdin > <https://www.linkedin.com/in/kang-li-84949a154/>. > > [image: IMG_7136.jpg] > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/e8214398-75dc-42e3-9871-a5661459e1dcn%40googlegroups.com.