It is wrong or at least useless since B(t) appears in the integral. A
correct and simple result is given by the 1st_linear hint:
In [111]: dsolve(expr, hint='1st_linear')
Out[111]:
⎛ ⌠ ⎞
⎜ ⎮ ⌠ ⎟ ⌠
⎜ ⎮ -⎮ a(t) dt ⎟ ⎮ a(t) dt
⎜ ⎮ ⌡ ⎟ ⌡
B(t) = ⎜C₁ - ⎮ ℯ dt⎟⋅ℯ
⎝ ⌡ ⎠
In [112]: sol = dsolve(expr, hint='1st_linear')
In [113]: checkodesol(expr, sol)
Out[113]: (True, 0)
The incorrect result comes from the 1st_exact solver. It's possible
that 1st_exact shouldn't match this or that there's a bug in the
1st_exact solver.
--
Oscar
On Fri, 8 Apr 2022 at 23:32, Aaron Meurer <[email protected]> wrote:
>
> It does look wrong, according to checkodesol(). Can you open an issue
> in the SymPy issue tracker for this?
>
> Aaron Meurer
>
> On Thu, Apr 7, 2022 at 7:58 PM kang li <[email protected]> wrote:
> >
> >
> >
> > On Friday, April 8, 2022 at 2:43:18 AM UTC+1 kang li wrote:
> >>
> >>
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