This is a very very bad advice. I almost feel like hitting you for this.
DO NOT JUDGE HOMEWORKS. DO NOT SEPARATE knowledge into "base " and "tangential" especially when you are learning something in a course because many times th so called "tangential knowledge" is there to reinforce your "base knowledge".
I will take an example that you gave. If a student takes Algorithm design class, you would separate the class into the core design principles as "base" and the other as "tangential". However, the concrete algorithms are there to reinforce the design principles, to describe the abstraction layers that we have built etc. If a student doesn't work hard to learn about the working of the algorithm, he would probably miss out on important aspects like the power of invariance, the power of recurrence, the hurdle in analyzing the recurrence, the nonintuitive correctness of these algorithms. These are all implicit knowledges. The teacher would probably just mention it and move on in the lecture.
But the assignments, the problem sets, the midterm, the final exam are there to reinforce all these small lessons that would probably be missed. DO NOT JUDGE HOMEWORKS. As a student you may have no idea about what is important and what is not. Even if you feel you are not learning anything, do them, redo them, revise them and perform well in them. You never know the skills that you may pick up along the way that will make you a better computer scientist.
tl;dr
If you seriously doubt the purpose of the assignment, ask the teacher or the TA.
DO NOT JUDGE HOMEWORKS. DO NOT SEPARATE knowledge into "base " and "tangential" especially when you are learning something in a course because many times th so called "tangential knowledge" is there to reinforce your "base knowledge".
I will take an example that you gave. If a student takes Algorithm design class, you would separate the class into the core design principles as "base" and the other as "tangential". However, the concrete algorithms are there to reinforce the design principles, to describe the abstraction layers that we have built etc. If a student doesn't work hard to learn about the working of the algorithm, he would probably miss out on important aspects like the power of invariance, the power of recurrence, the hurdle in analyzing the recurrence, the nonintuitive correctness of these algorithms. These are all implicit knowledges. The teacher would probably just mention it and move on in the lecture.
But the assignments, the problem sets, the midterm, the final exam are there to reinforce all these small lessons that would probably be missed. DO NOT JUDGE HOMEWORKS. As a student you may have no idea about what is important and what is not. Even if you feel you are not learning anything, do them, redo them, revise them and perform well in them. You never know the skills that you may pick up along the way that will make you a better computer scientist.
tl;dr
If you seriously doubt the purpose of the assignment, ask the teacher or the TA.