In my maths BSc, I've never had this happen. I've seen it in textbooks, yes, but there I kind of understand it—it would otherwise just bloat the textbook, and m

In my maths BSc, I've never had this happen. I've seen it in textbooks, yes, but there I kind of understand it—it would otherwise just bloat the textbook, and many people use textbooks in class with a teacher anyway. I've usually either had practice questions with solutions directly provided or assignments to hand in (usually this was optional). The solution to these assignments would be posted after the due date and of course, you would get your submission checked by a TA.