I will post answers to questions about the course which arrive by email.

(I'll remove identifying information, so don't be afraid to ask!).

1. ---

   >I am doing the homework for 7.2 and i am having trouble with 
   >number 19.  I know we did some things with birthday 
   >probability in class, but i don't think you ever told us how 
   >to calculate the birthday probability.  Can you please send 
   >me in the right direction. 
   
   
   We haven't talked about that yet, but will do so first thing on Wednesday;
   that discussion may answer your question.
   
   In the meantime, one way to think about it is this:
   
   1) What are the total number of pairs of birthdays that two people could have?
   (This is discussed in the book).  This is the number of  ``outcomes''
   
   2) In how many of these outcomes are both people born on December 9?
   
   
   
   
   

1. ---

   >I'm having trouble starting number 
   >15 and 18 on 4.1 and I was wondering if you could give me 
   >some insight on these problems. 
   
   
   #15:   Use the Pythagorean theorem on one of the two right triangles which you
   see in the picture.  (You need to know how many feet are in a mile.)
   
   #18:  How can you tell if a triangle is a right triangle by measuring the three sides and using the
   Pythagorean theorem?       For example, a triangle with sides 3, 4 and 5 has to be a right triangle.
   But a triangle with sides 3, 4, and 6 can't be a right triangle. 
   Use this idea on the triangle formed by two sides of the patio and the diagonal.
   

1. ---

   >Hey I was wondering what we were supposed to do on number 24 
   >on 2.2. It says to play with a friend but im not sure how or 
   >what were supposed to record on our paper.
   
   
   There's not much to write down.
   In the second game, the question asks you to record
   the number of sticks removed at each turn, so you
   can write this down. 
   
   

2. ---

   >I am still confused on what you want us to do on section 2.3 numbers 5 and 7.
   > For number 5 are we just supposed to list some characteristics of a prime
   > numbers, or do you want actual numbers?
   
   
   
   In number 5:  you should describe an infinite list of actual numbers which 
   are not prime.
   
   In number 7:  You should find the smallest number n bigger than one for
   which N=1x2x3x.....xn +1 is NOT a prime number.
   You should compute N when n=2.  Then compute N when n=3.  
   Then compute N when n=4, etc.