[weinzierl]

> Isn't this the very reason that homework assignments exist?

Absolutely. It is also why I will never understand why it is considered a virtue (especially in the maths and physics community) to set assignments without exemplary solution. I'm not asking to give this exemplary solution to students right away, but it should definitely exist and be given when students have shown honest effort and especially to weaker students that are struggling.

Instead the "left as an exercise to the reader" mentality is celebrated when in reality - in my opinion - it is almost always just a convenient excuse for the laziness of the professor at the expense of their students.

[Aune]

I have seen plenty of miss-use of solutions of the following though:

1. Struggle with exercise.

2. Check proposed solution.

3. Thinking that your understanding of the proposed solution constitutes an ability to solve it yourself.

This is analogous to the original problem, where you assume the ability to follow reasoning translates to being able to reproduce it.

The main use of exercises without solutions is to try and force students to go to their teachers and interact, so that someone can try to pinpoint what exactly the missunderstanding is.

This can probably be better done with assigned homework. However grading can be time consuming, so trying to filter so that only those that have problem with specific exercises come to see you is one way to try and get some time economy going.

Also yeah. This is better in course specific work sheets than in books, since books should be self contained enough to be usable without the guidence of TAs or professors.

[tormeh]

IMO mathy homework should always come with the correct end result to the questions. It allows the student to get instant feedback on whether they’re right or wrong. They’ll still have to work out the derivation of the answer.

[kaashif]

That works fine for some kinds of questions, but not for questions like "prove this group is cyclic" or "prove this function is holomorphic" - in those cases there is no answer separate from the derivation.

And those questions tend to be the hardest and most prone to bullshittery by students. Many times in exams I made up proofs that made no sense and hoped no-one would notice.

Often when given the end result of a computation students just make up some nonsense integral or something and pretend they evaluated it, even if they didn't. Not having the answer immediately at least forces an honest attempt.

Let's not kid ourselves, we were all students at one time and we know students are lazy.