# Homework #6 Results

### Homework #6 Results and Key

Mean: 82.4%; standard deviation: 21.9%

Most did quite well. Scaffolding provided by the textbook was no doubt a factor.

Many points were lost when folks did not follow instructions. If asked to use the Pumping Lemma, *use the Pumping Lemma*. If asked to use Theorem 11.1, *use Theorem 11.1*.

**Please** write complete proofs. Convincing your grader that you understand how the Pumping Lemma works is one thing. Convincing your grader that you can write a proof that will convince someone else that the language {} is not regular is quite a different thing. You need to do *both*.

A professor once told me: “When you write a proof, you must touch my heart. You must make me believe. You must make me believe in my heart that it is true.” Guess which professor this was. You have *one* guess.

**Please** write legibly or type. If one cannot read your work, you will lose points.

**No more fringe. I will take off points on all future homework if there’s spiral bound fringe attached or if your work is not stapled in the upper left-hand corner.**

Answer key can be downloaded here.