it's also worth noting that the forum does have a homework policy: FAQ: Homework Policy
In short, homework inspired questions are OK, but try to parse your question down to the bit you're hung on and make a reprex of just that bit. Also make sure you format your posts so they are readable. You'll find that helpers are more forthcoming if you don't make them jump through a lot of hoops to see what you're doing (thus the reprex).