Purpose: test student's ability to gather, organize, and present information
Usually you get to choose a topic, but perhaps it was assigned. At least you probably chose the class on the basis of interest.
Your audience is in fact usually the instructor, but you should write as though you are writing to classmates.
You need to prove that you know the basic ideas. You must not assume the instructor (who probably can infer them from your writing) will fill them in for you.
You want to get a good grade, but the instructor's standards will almost always require good presentation, and enthusiasm for your topic helps
In business, corresponds to internal report presented to boss or coworkers for their information, but not external use
Length: 5-20 pages
Preparation time: several weeks