Problems and Contests (Math 394) --- Fall 2008
Do you enjoy solving problems? Do you like contests?

The undergraduate mathematics seminar on Problems and Contests may be for you. Come and participate when you can. For the Fall 2008 semester, we meet
Thursday,   2:10 – 3:00 pm,   in Math 108.

Here is our first set of problems for the Fall 2008 semester.
  1. Sally selects 2008 points in the plane so that no three are collinear. Cathy colors them so that half of the points are colored Blue while the other half are colored Green. Penelope then pairs each Blue point with a Green point and joins each pair with a line segment. Show that Penelope can do her pairing so that no two line segments intersect.
    This was problem 1 of our Lennes Competition in 2008.
  2. Note: 16 has prime factorization 24, 17 is prime, 18 = 2 * 32, 19 is prime, 20 = 22 * 5, and 21 = 3 * 7.
    1. A is the sum of 1 and three odd positive integers. What can be said about the prime factorization of A?
    2. B is the sum of 1 and three consecutive odd positive integers. What can be said about the prime factorization of B?
    3. C is the sum of 1 and the squares of three consecutive odd positive integers. What can be said about the prime factorization of C?
  3. Suppose g is a positive-valued function which is differentiable on the interval [a,b]. Prove there is some t in (a,b) such that
                 g'(t)         1           1
                -------  =  -------  +  -------
                 g(t)        a - t       b - t
  4. Given three points in the plane, construct a line such that the sum of their distances to the line is a minimum.
  5. Farmer Jones has 65 hens. If he had one more solid colored hen, then exactly one-third of his hens would be speckled. From years of experience, Farmer Jones knows that one-half of the speckled hens will lay speckled eggs and that each hen-and-a-half will lay an egg-and-a-half in a day-and-a-half.
    1. After how many full days will Farmer Jones have five dozen speckled eggs to sell?
    2. After how many full days will Farmer Jones have four dozen speckled eggs to sell?
  6. Let P be a nonconstant polynomial with positive integer coefficients. Prove that if N is a positive integer, then P(N) divides P(1+P(N)) if and only if N = 1.
    This was problem B-1 of the Putnam Competition in 2007.

Last modified: 11 September 2008, Thursday 15:53