# Rhea Section for MA375 Professor Walther, Spring 2016

This page refers to the "Lecture Notes in Discrete Mathematics" of MA 375 in Spring of 2016, by Uli Walther. To edit: click on "user" and choose "log in" in the drop down menu. Enter Purdue ID and password. After logging in, click "actions" and select "edit". Then make the requisite changes in the editor you will see. Then click "save page" all the way down. Check that you wrote what you wanted.

Do not delete or edit previously listed typos.

Please list any typo found in the course notes below. Mimic the first two entries: indicate page, line from above (positive numbers) or from the bottom (negative numbers), old text and new text. Add a new line for each typo.

• 1. list here the first typo
• 2. and here the next
• etc.
• Not a typo, but a note. The way that the chapter numbers change with both a change in chapter and a change in section is very confusing especially for when trying to find the hw problems. (For example: Chapter 2 Arithmetic, 1. The Integers, 1.1 Prime Numbers, Definition 2.1 ... , with 2. Arithmetic and 1. The Integers then alternating at the top of the page)
• 1. page 22, 1st line. Original text reads "\$1.000.000 to crack it". English convention is to use "," for digit grouping and "." for decimal marks. New text: "1,000,000 to crack it."
• 2. page 27, line 3-6. In line 3 you state that n=10, then have it substituted in line 4 (Z/10Z), go back to using n in line 5 (Z/nZ) and then finally use 10 again in line 6.
• 3. page 52, the coefficient of 3rd term after colon of THEOREM 4.12(Binomial Theorem) is not correct.
• 4. page 54, line 3. there are two "the" before the word "separators".
• 5. page 52, The power of 'x' should be r and n-r for 'y' in binomial expansion of(x+y)^n.(Theorem 4.12)
• 6. page 55, line 30. In the first sentence, the dealer is a man "his". In the second sentence, the dealer is a woman "she".
• 7. page 55, line 31. Grammar is weird. Should read "How many anti-symmetric ways are there to arrange the cars?" (Placement of verb is different in English vs German)
• 8. page 55, line -7. Should be: (a) have no sides in common.
• 9. page 55, line 30. It should be best cars or just cars instead of objects.
• 10. page 57, line 28 and 30. Should be : catching 'fishes' from the pond and eating some of them.

(Correction 10 is incorrect. The plural of fish is fish)

• 11. page 64, line 29 : We should use "sequence" or "row" instead of "array".
• 12. page 64 line -21: should be red, blue, and green
• 13. page 64 line -10: remove the word "the". Should simply be "divide n people".
• 14. page 64, line 33: remove the word "the" from in how many ways you can divide "the" n people.
• 15. page 74, line 2: the first sum, evaluated from p=1 to infinity, is multiplied by x an extra time. It should be either x*sum(a*x^p) or sum(a*x^(p+1))
• 16. page 30, last line. Original text: "Obviously, a similar thought works for 9 instead of 9..." New text: "9 instead of 3"

(Suggestion: When you are talking about more than one fish(same species), the plural fish is more commonly used than fishes but when you are talking about more than one kind or species of fish, fishes is used.)

• 17. page 71, line ~11: It says "We will study three methods for co muting Ga(x)." I believe that this should be computing and not co muting.
• 18. page 50, in the explanation of Version 1., C(n,r-n) should be C(n,n-r).
• 19. page 79, second to last line in exercise 6.8 the word "that" is unnecessarily repeated. "Show that that each collection of natural numbers..."
• 20. page 94, line 8, 10>=((5-2)/5)*5+2 should be corrected to 10>=((5-2)/5)*15+2.
• 21. page 97, line 2, f,e,f,d,D should be f,e,v,d,D.
• 22. page 101, line 10, erased if called ==> erased is called.
• 23. page 112, line 7, "she" should be "the".
• 24. page 75-77, going from chapter 5 to chapter 6 there is no page 76
• 25. page 31-33, going from chapter 2 to chapter 3 there is no page 32
• 26. page 113-115, going from chapter 6 to the "List of symbols" there is no page 114