My university course uses Maxima for optimization modules and essentially none of the examples from the textbook work as they should. Official documentation is sparse and often unhelpful too. The functions output Lisp stacktraces if you do something wrong, rather than actually catching errors and printing some human-friendly message that describes the problem and which particular argument caused it without having to dig into Maxima source code. It would be great CAS software if it was a bit more polished, but unfortunately that is unlikely to ever change - it hasn't in the last 4 years that I've used it at least.