IMO 1989 Shortlist

IMO 1989 Shortlist — 32 problems. 32 problems.

32 items

IMO 1989 Shortlist

32 problems · Source: IMO Compendium

Problems

# Origin Problem
1 AUS Let ABC be a triangle. The bisector of angle A meets
2 AUS Ali Barber, the carpet merchant, has a rectangular piece of
3 AUS Ali Barber, the carpet merchant, has a rectangular piece of
4 BUL Prove that for every integer n > 1 the equation
5 COL Consider the polynomial p(x) = xn+nxn−1+a2xn−2 +\cdot \cdot \cdot+an
6 CZS For a triangle ABC, let k be its circumcircle with radius r. The
7 FIN Show that any two points lying inside a regular n-gon E can
8 FRA Let R be a rectangle that is the union of a finite number of
9 FRA For all integers n, n \geq0, there exist uniquely determined
10 GRE Let g : C \toC, w \inC, a \inC, w3 = 1 (w ̸= 1). Show that
11 HUN Define sequence an by 
12 HUN At n distinct points of a circular race course there are n cars
13 ICE The quadrilateral ABCD has the following properties:
14 IND A bicentric quadrilateral is one that is both inscribable in
15 IRE Let a, b, c, d, m, n be positive integers such that a2+b2+c2+d2 =
16 ISR The set {a0, a1, . . . , an} of real numbers satisfies the following
17 MON Given seven points in the plane, some of them are connected
18 MON Given a convex polygon A1A2 . . . An with area S, and a point
19 MON A positive integer is written in each square of an m\timesn board.
20 NET Given a set S in the plane containing n points and satis-
21 NET Prove that the intersection of a plane and a regular tetrahedron
22 PHI Prove that the set {1, 2, . . ., 1989} can be expressed as the
23 POL We consider permutations (x1, . . . , x2n) of the set {1, . . . ,
24 POL For points A1, . . . , A5 on the sphere of radius 1, what is the
25 KOR Let a, b be integers that are not perfect squares. Prove that if
26 KOR Let n be a positive integer and let a, b be given real numbers.
27 ROM Let m be a positive odd integer, m \geq2. Find the smallest
28 ROM Consider in a plane \Pi the points O, A1, A2, A3, A4 such that
29 ROM A flock of 155 birds sit down on a circle C. Two birds Pi, Pj are
30 SWE For which positive integers n does there exist a positive
31 SWE Let a1 \geqa2 \geqa3 be given positive integers and let N(a1, a2, a3)
32 USA The vertex A of the acute triangle ABC is equidistant from