IMO 1986 Shortlist

IMO 1986 Shortlist — 21 problems. 21 problems.

21 items

IMO 1986 Shortlist

21 problems · Source: IMO Compendium

Problems

# Origin Problem
1 GBR Find, with proof, all functions f defined on the nonnegative
2 SWE Let f(x) = xn where n is a fixed positive integer and x =
3 USA Let A, B, and C be three points on the edge of a circular
4 CZS Let n be a positive integer and let p be a prime number, p > 3.
5 FRG The set S = {2, 5, 13} has the property that for every
6 NET Find four positive integers each not exceeding 70000 and each
7 FRA Let real numbers x1, x2, . . . , xn satisfy 0 < x1 < x2 < \cdot \cdot \cdot <
8 USA From a collection of n persons q distinct two-member teams
9 GDR Prove or disprove: Given a finite set of points with integer
10 HUN Three persons A, B, C, are playing the following game: A k-
11 BUL Let f(n) be the least number of distinct points in the plane
12 GDR To each vertex Pi (i = 1, . . . , 5) of a pentagon an integer
13 FRG A particle moves from (0, 0) to (n, n) directed by a fair coin.
14 IRE The circle inscribed in a triangle ABC touches the sides
15 NET Let ABCD be a convex quadrilateral whose vertices do not
16 ISR Let A, B be adjacent vertices of a regular n-gon in the
17 CHN Let A, B, C be fixed points in the plane. A man starts
18 TUR Let AX, BY, CZ be three cevians concurrent at an inte-
19 BUL A tetrahedron ABCD is given such that AD = BC = a;
20 CAN Prove that the sum of the face angles at each vertex of a tetra-
21 TUR Let ABCD be a tetrahedron having each sum of opposite sides