PROBLEMS FOR NOVEMBER
Solutions should be submitted to
Dr. Dragos Hrimiuk
Department of Mathematics
University of Alberta
Edmonton, AB T6G 2G1
no later than
December 31, 2000.
- 43.
-
Two players pay a game: the first player thinkgs
of n integers x1, x2, ¼, xn, each with one
digit, and the second player selects some numbers
a1, a2, ¼, an and asks what is the vlaue
of the sum a1x1 + a2x2 + ¼+ anxn. What is the
minimum number of questions used by the second player to find
the integers a1, x2, ¼, xn?
- 44.
-
Find the permutation { a1, a2, ¼, an }
of the set { 1, 2, ¼, n } for which the sum
S = |a2 - a1 |+ |a3 - a2 |+ ¼+ |an - an-1 | |
|
has maximum value.
- 45.
-
Prove that there is no polynomial
p(x) = an xn + an-1xn-1 + ¼+ a0
with integer coefficients ai for which
p(m) is a prime number for every integer m.
- 46.
-
Let a1 = 2, an+1 = [(an + 2)/(1 - 2an)] for n = 1, 2, ¼.
Prove that
(a) a
n ¹ 0 for each positive integer n;
(b) there is no integer p ³ 1 for which an+p = an for every integer n ³ 1 (i.e., the sequence is
not periodic).
- 47.
-
Let a1, a2, ¼, an be positive real
numbers such that a1 a2 ¼an = 1. Prove that
where s = 1 + a
1 + a
2 +
¼+ a
n.
- 48.
-
Let A1A2 ¼An be a regular n-gon and
d an arbitrary line. The parallels through Ai to
d intersect its circumcircle respectively at
Bi (i = 1, 2, ¼, n. Prove that the sum
S = |A1B1 |2 + ¼+ |AnBn |2 |
|
is independent of d.