Math 302, Transition to Higher Mathematics
(2:25-3:40 PM MW in LA-3)


Final exam: The final exam will be at 2-4 on Wed 5/9 in the usual classroom (LA-3). The final is cumulative. You may bring one side of a letter-size sheet (8.5" by 11") of handwritten notes to the exam. You may use both sides of a sheet half that size if you prefer.

Office hours during final period: 11-1 on Wed, 5/9 and 1:30-3:30 on Mon 5/14. Syllabus: Here is the syllabus.

Online resources:
Homework: The homework is due at 7 PM on the due date in the envelope on my office door.

Assigned
Due
Read
Exercises
1/22
1/31
1.1, 2
Write a brief (about one or two paragraphs) description of what you think mathematics is. Don't do research, I want to see what you think about math.
1.2.2, 3, 5, 9
1/29
2/5
1.2, 3
1.2.10, 13, 14
2/5
2/12
1.3, 4
Familiarize yourself with Block World (link above). Using the default setup, come up with 10 different statements, 5 of which are true and 5 of which are false. Use all of the five logical operations (/\, \/, =>, <=>, and ~)in at least two statements each. You may combine the operations any way you want, as long as each shows up in at least two different statements. You may find it easiest to submit your solutions by copying them into an e-mail to me. If you prefer to print them or write them down by hand, that's fine too.

1.3.1-3
2/12
2/19
1.4
To complete this Block World project, you first need to find yourself a partner from the class to work with. Read the note on saving your work in Block World. This project will be easier to do if you can save your work.

Start by clearing the board. Then place a few (say 5-10) polygons on the board. Make sure you give each a name, so you can refer to them later. Make up 5 true and 5 false statements about your board. Don't use "for all" and "there exists" because we haven't covered these, but do use /\, \/, =>, <=>, and ~.  Verify your statements (Eval all). Print or save what you've created, but don't show it to your partner. Clear the board again and swap statements with your partner. (You can just give him/her the file with your saved statements, but not the one with your saved board!) Tell your partner which statements were true and which were false.
Now that you have your partner's statements, make up a board with polygons which satisfies those statements, i.e. makes the ones that are supposed to be true true, and the ones that are supposed to be false false. Verify your statements (Eval all). Print or save again.

You'll turn in the board and statements you made up as a challenge to your partner, and the board that you made up to satisfy your partner's statements. Make sure you write both your name and your partner's name on each. You may submit your work on paper (as a printout), or by e-mail (attach both the saved board file and the saved statements, that's 4 files total).

1.3.4(1)-(3), 5(1)-(3), 8, 12
2/19

1.4
No new homework.
2/26
3/7
1.4, 5
1.4.1, 2
3/7
3/14
1.5
1.4.3, 4
1.5.1
3/14
3/21
1.5, 2.1
1. Use the default statements that come with Block World. Translate statements 3-6 and 8, 9 into reasonably natural English sentences.  This means you should avoid using variables and other mathematical technicalities in your sentences. (Hint: You can use Block World to experiment with parts of the statements you need to translate to make sure you understand what they mean. You can even change the board to test that you sentences always have the same truth values as the original statements. Take advantage of the interactivity the software offers.)

2. Translate the following sentences into statements that Block World understands:
(a) Every triangle is smaller than every pentagon.
(b) Every pentagon is the same size as some square.
(c) There is a triangle that is between a square and a pentagon.
(d) There is only one large pentagon.
(e) Every medium pentagon is in the same column as a large triangle.

(Hint: Again, changing the board lets you test if your constructs work as they should.)

1.5.6
3/21
4/4
2.1, 2
1.5.8, 10
1.5.11.(1), (3)
1.5.12.(2), (4)
4/4
4/11
2.3, 4
2.2.2, 4, 6, 7
4/11

2.4, 5
No new homework this week
4/18
4/25
2.5, 6
2.3. 3, 8
2.4. 2, 3, 9
4/25
5/4
(This is a Friday!)
3.1-3
2.5.4.(1),(2)
2.5.9
3.2.4, 15. (1), (4)-(7)  (Be sure to explain why!)
3.3.9, 14
5/3
5/7
3.3, 4.1
Write a brief (about one or two paragraphs) description of what you think mathematics is. Don't do research, I want to see what you think about math.

Recommended text: A. Cupillari, The nuts and bolts of proofs. The 3rd edition is current.

The problem of the week:

  1. Posted 1/24. This is for warm-up, you can't get credit for it. It's a great problem to think about if you don't already know the solution, but it's too easy to find the solution on the www to get credit for it.
    Once upon a time, there was a poor vagabond who was captured as he traveled through a faraway kingdom. The king said "You trespassed in my kingdom without my permission. This calls for punishment. But I am in a playful mood today, so I will give you a chance to earn your freedom. There are two doors over there, each guarded by a soldier. One door leads to the jail, the other leads to the courtyard. I won't tell you which is which. But I'll let you ask one of those soldiers one yes/no question. I must warn you that one of the soldiers answers thruthfully, but the other always lies. Remember, you are only allowed one question. Afterwards, you must choose which door to enter. If you choose the one that leads outside, you are free to go. But if you choose the one that leads to the jail, you will be imprisoned forever." What question should the vagabond ask to guarantee he can choose the right door?

  2. Posted 1/24, due 1/31
    In the distant country of Logica, there are two kinds of people: square shooters, who always tell the truth, and liars, who always lie. On one of your travels to Logica, you meet a local inhabitant. You would like to know if she is a square shooter or a liar. How can you tell by asking her only one yes/no question? Unfortunately, science and culture in Logica are quite different from ours, so you can't ask her a question like "Is 1+1=2?" or "Was George Washington the first president of the USA?" She simply won't know the answer.

  3. Posted 1/31, due 2/14
    On one of your explorations in Logica, you travel to the northwestern corner of the country. The people living there are still either square shooters or liars. They all understand English just fine, but because of a strange historic accident--which no one quite remembers--instead of yes and no, they say boo and bah. Unfortunely, we don't know which of these means yes and which means no. As you reach the first village, you run into a local inhabitant. He seems like a nice guy, but he could be either a square shooter or a liar. Surely, you'd like to know. How can you tell by asking him only one yes/no (or boo/bah) question?

  4. Posted 2/7
    Unfortunately, no one has turned in a solution to last week's puzzle. We wouldn't want to move on until we resolve the important question of telling square shooters and liars apart in northwestern Logica. So I have extended the deadline on this question until next week. Here is a hint that might help: What question would you ask that inhabitant of northwestern Logica if you wanted to find out what boo and bah mean?

  5. Posted 2/14 (Valentine's day!), due 2/21
    There is an old romantic story in Logica about a young square shooter who wanted to propose to his girlfriend. He was quite mischievous though, so instead of giving his girlfriend an engagement ring in a box, he presented her with three boxes. He explained to her that the ring was in one of the boxes and if she chose the right box, he would propose to her. If not, he would have to rethink. Each box had two inscriptions on it. The inscriptions were made by two different artists, one of whom was a square shooter, while the other was a liar. But none of the boxes had both inscriptions made by the artist that was a liar. She could read the inscriptions, but she would not be allowed to open, lift, or shake the boxes or pull any other trick to guess which might have the ring. The inscriptions on the red box were "The ring is not in this box" and "The ring is made of gold." The inscriptions on the blue box were "The ring is not in this box" and "The ring is in the red box." The inscriptions on the green box were "The ring is not in the red box" and "The ring is made of platinum." As the story has it, she really wanted to marry the young man and she was smart so she chose the right box. Which box did she choose and why? Can you tell what the ring was made of?

  6. Posted 2/21, due 3/5 (because I won't be here on 2/28)
    The island of Ekouna is under the administration of Logica. The original population of Ekouna consisted of normal people, who would sometimes tell the truth and sometimes lie. The current population is mixed and consists of square shooters, liars, and normals. On one of your trips to Ekouna, you spot an advertisement for an attractive job and you decide to apply for it. The ad says the successful applicant must be normal and must provide evidence of this. (Discrimination based on veracity is legal on Ekouna.) Fortunately, you are indeed normal. Terseness is a highly prized attribute on Ekouna, so the odds of you getting the job depend heavily on your ability to prove you normalness without talking too much. What is the least number of true statements you can make in your job application to prove that you are normal?

  7. Posted 3/5, due 3/14
    Math puzzles are very popular in Logica. I once heard the following from an inhabitant there. Imagine you are in a dark room with a table and 100 casino chips on the table. Each chip has one side red and one side green. 24 of the chips are turned so that the red side is up. The remaining chips have the green side up. You are allowed to flip chips if you wish. Unfortunately, it's dark so you can't see the chips and can't tell which side is up. The two sides of the chips are identical to the touch. How can you separate the chips into two piles so that each pile has the same number of chips with the red side up? (The piles don't have to have the same number of chips).

  8. Posted 3/14, due 3/21
    Here is another popular math puzzle from Logica. The king's daughter and a young knight were in love. Unfortunately, the king was opposed to their marriage. So the couple decided to elope. The princess wanted to put him to one last test of intelligence before escaping with him. After all, marrying a dummy would be a big embarrassment for a princess in Logica. So she gave him 13 golden keys. She told him that in fact 12 of the keys were made of a gold alloy. But one key was made of pure gold and this would open the door to the princess's room. None of the other keys would work. The 12 fake keys all weighed exactly the same, but the real key's weight was slightly different. The difference was not enough to feel by hand. She also gave him a balance and told him he was allowed three weighings to find the right key. How would you do this? BTW, the young knight figured out how to find the right key, eloped with the princess, and they lived happily ever after. Rumor has it that even the king forgave them eventually.

  9. Posted 3/21, due 4/4
    There is a bird in the San Diego Zoo, which has the following curious property. Everytime this bird eats birdseed, all the other birds in the zoo will eat at the same time. Find a picture of this bird and explain why it has this curious property. (The picture doesn't have to show the particular bird in the SD Zoo, a picture of a bird of the same species is OK. You can e-mail me the picture or a link to it.)

  10. Posted 4/4, due 4/11
    There was once a wise king who had two daughters. One day, a young prince showed up in his court to ask to marry one his daughters. Before the prince could say anything, the king spoke: "I understand you came to ask for my daughter. I am feeling playful today, so I will challenge you to a game. I will ask you to make a statement. If the statement is true, I will let you marry my older daughter. But if your statement is false, I will not allow you to marry her." The prince knew that if he married the king's older daughter, he would eventually inherit his kingdom. But he really liked the younger daughter and he came to ask for her hand. He agreed to the game and made a statement. When the king heard it, he realized that the only way he could keep his word was if he let the prince marry his younger daughter. What may the prince have said to the king and how did it force the king to give him his younger daughter?

  11. Posted 4/11, due 4/18
    One day, two mathematicians ran into each other while riding the bus. They had not seen each other in ages, and had the following conversation.
      Mathematician1: "You know I have three children now?"
      Mathematician2: "How nice! How old are they?"
      Mathematician1: "If you multiply their ages together, you get 36."
      Mathematician2: "I still don't know how old they are."
      Mathematician1: "If you add their ages together, you get the number on this bus."
      Mathematician2: "That still doesn't tell me."
      Mathematician1: "The youngest is a girl."
      Mathematician2: "Now I know."
    How old are the children? How can you tell?

  12. Posted 4/18, due 4/25
    Is there a sequence of 100 consecutive positive integers such that not one of them is a prime number? (Hint: You can solve this problem similarly to the proof that there are infinitely many primes.)

  13. Posted 4/25, due 5/4
    Here is one last puzzle about the country of Logica. Remember that every native of Logica is either a square shooter or a liar. Among the natives I know in Logica, the following is true. For every native A, there is a native B such that B says both A and B are liars. How many natives do I know?
The problem of the fortnight: The Mathematics Department in San Diego posts a new fun problem every two weeks.  You can submit solutions to them by mail, or if you happen to go to SD, in person.  Winners receive prizes.

Exam solutions:
Useful links: The links below lead to sites with encyclopedias of math terms.  You can use them to find definitions, examples, and some theorems.
Some scholarship opportunities for prospective teachers: