The original post does not say anything about the teacher. Being picky, we can not even know the student's character from it. Is he lazy? Maybe he/she is so confused by the problem not knowing even what precisely to ask (the teacher) to get more clarity?
Anyway, there have been some very good answers with hints and links, like the step-by-step post. After all, it's a valuable answer if the OP does want to take some effort, no matter if he/she has been too lazy, not intelligent enough, or a bad teacher's student.
By the way, the node's title is really silly.
