Every student will be allowed three late-days per quarter. After your three late-days have been used up, we will not accept any more late homework.
Partial credit on the homework is assigned by the reader, whose decisions are final. Incorrect solutions might get partial credit, but clearly a student who recognizes that the solution is incorrect is doing better than a student who has the same solution but believes that it is correct. So we will give 1/4 credit for writing "I don't know", and then possibly more partial credit for any partial solutions, insights into the problem, etc, which you can give.
Often the answer to a problem is not obvious, even to a graduate student, a professional, or a professor. There may be some problems you cannot solve.
I recommend that you try to solve all the problems on your own first, without help from friends, without using the Web, without checking other books, etc. Often there are many possible approaches that seem reasonable. By trying some approaches that don't work, you learn why they don't work. This helps you solve other problems later, recognize easy special cases when they arise, etc. If you immediately get the solution from somewhere else, even if you do learn the solution really well, you miss this experience.
While you are welcome to use books, the Web, or your friends for help with the homework, your solutions must be written up clearly in your own words. This means you should be alone, and not looking at any online or hardcopy reference materials. If you can write the solution under these conditions you can be sure you understand it, and you will be able to use your understanding on an exam.
Try to write your solutions clearly and succinctly. Use complete sentences. Poorly written solution may be marked down. Like writing an English paper, it is helpful to write a draft or an outline first. Typeset solutions are welcome; an acceptable compromise is to type the text, print it out, and then write in equations and pictures by hand. If you do write the text by hand please make a real effort to write neatly. The reader may mark down papers which are difficult to read (tiny writing, illegible writing, poor attempts to type equations in ACSII, etc.).
On the other hand, don't get so hung up on writing a perfect solution that you hesitate to write an imperfect solution and instead hand in nothing! We want to know that you are working on the problems and we want to give you credit for it!