You are encouraged to learn from each other. However, all the work you hand in must be your own. This means that you cannot look at another student's answer and copy or re-word it as your own.
If someone helps you with a homework assignment, please write their name on the top of your homework. This will not hurt you (provided your answer is your own), but it will help them.
If you are the student giving help, don't give away the answer. Rather, help the student arrive at the answer themselves.
If you are the student asking for help, don't ask for the answer. Rather, ask about the material. Your own answer must come from your own intuition. You must fully understand what you write and be able to explain your answer to the instructor.