## Assignment 19

Due Friday, April 12. (I know a few of you are planning on being gone this Friday. I’ll accept this on Monday from anyone without penalty.)

2. Multiply the number 0111010 by 2 in binary.
3. A combination lock on a safe requires you to know 5 numbers, each ranging from 0 to 63, and each thus requiring at most 6 digits to represent in binary. For example: $0_{10}=000000_{2}$ and $63_{10}=111111_{2}$. A spy is planning on sending you these numbers, each as a message $m$ that is 8 bits/digits in binary. The first two digits (on the left side of the binary number) form a parity check function $p(m)$ given by: $p(m)=\begin{cases}00\text{ if m has 1 or 0 ones}\cr 01\text{ if m has 2 or 3 ones}\cr 10\text{ if m has 4 or 5 ones}\cr 11\text{ if m has 6 ones}\end{cases}.$ For example, if you receive the message 11010111, then you know that the parity check function value is 11 while the message is 010111, but since these don’t match you know that the message has been scrambled and is not reliable. The correct parity function value for the message 010111 would be 10, meaning that the received message should be 10010111. This all being said, you receive the messages: $01010001,\quad 01110010,\quad 00000010,\quad 10100100,\quad\text{and}\quad 01010101.$ Which numbers, in base 10, are you sure are a part of the combination to the safe? Which are you not sure about?

## Assignment 18

Due Friday, April 5

Convert the following numbers from base-2 to base-10.

• 1011
• 110010

Convert the following numbers from base-10 to base-2.

• 18
• 154

## Assignment 17

Due Wednesday, April 3

1. Is it possible for a (male) member of the Warlpiri society to marry his sister? parent? aunt? first cousin? Explain how you know each of these to be possible or not.
2. Given that a mother is in $S_7$, her first generation offspring are always in $S_8$. What is the fewest number of generations needed for her to have a member of her family tree (children, grandchildren, great grandchildren, etc.) be in $S_2$? in $S_6$?
3. Which section number is the father of the mother of the mother of the father of a person in $S_3$ in?

## Assignment 16

Assignment 16 is posted and is due on Wednesday, March 20.

1. Using the Brower-Cousteau model, find a way of pointing out exactly how large of a distance a “light year” is. A light year is the amount of distance that light itself can cover in the span of a year. It has been measured as exactly 9,460,730,472,580,800 meters. I’ll talk about this problem in class on Monday.
2. Use the Brower-Cousteau model to consider statistics of your choice. Some examples include: differences in average incomes between developed and underdeveloped nations, gun crimes in developed nations, CEO pay over time, etc.

## Assignment 15

Assignment 15 is posted and is due on Friday. assignment 15 (pdf)

## Assignment 14

Assigment 14 is posted and is due Monday: assignment 14 (pdf)

## Assignment 13

Assignment 13 is posted and is due Wednesday, March 5. math2380-s2013-assign13 (pdf)

## Assignment 12

Assignment 12 is posted and is due on Friday, March 1. assignment 12 (pdf)

## Assignment 11

Notice that assignment 11 is due on Wednesday. It is a combination of the question that was asked after “Climate of Doubt” and of the equivalence relation review that we did on Friday.

Assignment 11 is posted and is due Wednesday, February 20. assignment 11 (pdf)

## Assignment 10

Assignment 10 is posted and is due Friday, February 15: assignment 10 (pdf)