- Extra credit problems will be open until we get the
**first complete solution**. - You
**DO NOT NEED**to turn in after we announce that the problem is solved (in the Class Announcements). So be sure whether the problem is still open before you turn in the extra credit assignment. - If the problem is still open, you may try to turn in a new solution until the problem is closed.
- You should directly turn in your solutions for the extra credit problems to me. Either plug-in my office under the door or e-mail to me. I may wait only 24 hours (to close the problem) after I receive first complete solution.

You may try the first extra credit problem now.

Extra Credit Problem 1 (closed!)

Extra Credit Problem 2(closed!)

Extra Credit Problem 3(closed!)

Extra Credit Problem 3-1 (closed!)

Extra Credit Problem 4 (closed!)

Extra Credit Problem 5 (closed!)

Extra Credit Problem 6 (closed!)

Extra Credit Problem 7 (closed!)

Extra Credit Problem 8 (closed!)

Extra Credit Problem 9 (closed!)

Extra Credit Problem 10 (closed!)

Extra Credit Problem 10-1 (closed!)

Extra Credit Problem 10-2 (closed!)

Extra Credit Problem 10-3 (closed!)

Extra Credit Problem 11 (closed)

Extra Credit Problem 12(closed)

Extra Credit Problem 12-1(closed)

Extra Credit Problem 13(closed!)