IMO 1982 Longlist

IMO 1982 Longlist — 37 problems.

37 items

IMO 1982 Longlist

37 problems · Source: IMO Compendium

Problem Origin Statement
AUS1 AUS It is well known that the binomial coefficients
AUS2 AUS Given a finite number of angular regions A1, . . . , Ak in a plane,
AUS3 AUS Given n points X1, X2, . . . , Xn in the interval 0 \leqXi \leq1,
BEL5 BEL Among all triangles with a given perimeter, find the one with
BEL6 BEL On the three distinct lines a, b, and c three points A, B, and
BEL7 BEL Find all solutions (x, y) \inZ2 of the equation
BRA9 BRA Let n be a natural number, n \geq2, and let \varphi be Euler’s function;
BRA10 BRA Let r1, . . . , rn be the radii of n spheres. Call S1, S2, . . . , Sn the
BRA11 BRA A rectangular pool table has a hole at each of three of its
BRA12 BRA Let there be 3399 numbers arbitrarily chosen among the first
BUL13 BUL A regular n-gonal truncated pyramid is circumscribed around
CAN15 CAN Show that the set S of natural numbers n for which 3/n
CAN18 CAN You are given an algebraic system admitting addition and
CZS20 CZS Consider a cube C and two planes \sigma, \tau, which divide Euclidean
CZS21 CZS All edges and all diagonals of regular hexagon A1A2A3A4A5A6
FIN23 FIN Determine the sum of all positive integers whose digits (in base
FIN24 FIN Prove that if a person a has infinitely many descendants (chil-
FRA26 FRA Let (an)n\geq0 and (bn)n\geq0 be two sequences of natural numbers.
FRA28 FRA Let (u1, . . . , un) be an ordered ntuple. For each k, 1 \leqk \leqn,
FRA29 FRA Let f : R \toR be a continuous function. Suppose that the
GBR33 GBR A sequence (un) of integers is defined for n \geq0 by u0 = 0,
GDR34 GDR Let M be the set of all functions f with the following proper-
GDR35 GDR If the inradius of a triangle is half of its circumradius, prove
POL38 POL Numbers un,k (1 \leqk \leqn) are defined as follows:
POL39 POL Let S be the unit circle with center O and let P1, P2, . . . , Pn
POL40 POL We consider a game on an infinite chessboard similar to that of
POL42 POL Let F be the family of all k-element subsets of the set
TUN43 TUN (a) What is the maximal number of acute angles in a convex
TUN44 TUN Let A and B be positions of two ships M and N, respectively,
USA46 USA Prove that if a diagonal is drawn in a quadrilateral inscribed
USA47 USA Evaluate sec′′ \pi
USA48 USA Given a finite sequence of complex numbers c1, c2, . . . , cn, show
USA49 USA Simplify
USS50 USS Let O be the midpoint of the axis of a right circular cylinder.
USS51 USS Let n numbers x1, x2, . . . , xn be chosen in such a way that
USS52 USS We are given 2n natural numbers
VIE56 VIE Let f(x) = ax2 + bx + c and g(x) = cx2 + bx + a. If |f(0)| \leq1,