Jeremy Monat

@asmeurer When we met, I recall you discussing using `Derivative` vs. `diff` when expressing derivatives in differential equations to be solved, but my notes don't include what the recommendation is....

### `Derivative` vs. `diff` I wondered whether we might want to recommend `Derivative` in case the user has already defined the function, so I checked whether using `Derivative` vs. `diff`...

Do folks think it's worth discussing `hint` and `classifiy_ode` (they're related topics, about how to try to solve an ODE)? @asmeurer was unsure, so I'd appreciate others' thoughts.

> Was it the intention to make `dsolve_system` a user function as listed on the [ODE page](https://docs.sympy.org/dev/modules/solvers/ode.html?highlight=ode#dsolve-system)? [`dsolve_system` is called by `dsolve` for iterables](https://github.com/sympy/sympy/blob/master/sympy/solvers/ode/ode.py#L559) (multiple equations); is there a reason...

> There seem to be a lot of changes to runtests.py here? Did you run some sort of autoformatter on it? Oops, yes. I'll undo the autoformatter changes, and just...

Note to self: Just waiting on #23802 to be merged, then will link to `solve-system-of-equations-algebraically.md` in Alternatives to Consider

It seems like this has been fixed, at least for the original example: ```py >>> from sympy import symbols >>> x, y = symbols("x, y") >>> (x*y).evalf(subs={y:0}) 0 ``` Relates...

Another thought is to return each solution as a dictionary of symbol-expression pairs so it's obvious which symbol corresponds to which expression, and easy to extract an expression by subscripting...

For some reason unrelated to this pull request I believe, [optional-dependencies (pypy-3.8, false)](https://github.com/sympy/sympy/actions/runs/3049205988/jobs/4915054679#logs) and [optional-dependencies (3.11.0-alpha - 3.11, true)](https://github.com/sympy/sympy/actions/runs/3049205988/jobs/4915054741#logs) give errors on the same file: FileNotFoundError: [Errno 2] No such...

> I wonder if we should try to make the example blocks more self-contained here. Each block here cannot be copied and run on its own because it depends on...