IMO 1979 Longlist

IMO 1979 Longlist — 55 problems.

55 items

IMO 1979 Longlist

55 problems · Source: IMO Compendium

Problem Origin Statement
BEL2 BEL For a finite set E of cardinality n \geq3, let f(n) denote the
BEL3 BEL Is it possible to partition 3-dimensional Euclidean space into
BEL5 BEL Describe which natural numbers do not belong to the set
BEL6 BEL Prove that 1
BRA7 BRA M = (ai,j), i, j = 1, 2, 3, 4, is a square matrix of order four.
BRA8 BRA The sequence (an) of real numbers is defined as follows:
BRA9 BRA The real numbers \alpha1, \alpha2, \alpha3, . . . , \alphan are positive. Let…
BUL11 BUL Prove that a pyramid A1A2 . . . A2k+1S with equal lateral edges
BUL13 BUL The plane is divided into equal squares by parallel lines; i.e.,
CZS14 CZS Let S be a set of n2 + 1 closed intervals (n a positive integer).
CZS16 CZS Let Q be a square with side length 6. Find the smallest integer
FIN18 FIN Show that for no integers a \geq1, n \geq1 is the sum
FIN19 FIN For k = 1, 2, . . . consider the k-tuples (a1, a2, . . . , ak) of positive
FRA21 FRA Let E be the set of all bijective mappings from R to R satisfying
FRA22 FRA Consider two quadrilaterals ABCD and A′B′C′D′ in an affine
FRA23 FRA Consider the set E consisting of pairs of integers (a, b), with a \geq
FRA24 FRA Let a and b be coprime integers, greater than or equal to 1.
FRG26 FRG Let n be a natural number. If 4n + 2n + 1 is a prime, prove
GDR30 GDR Let M be a set of points in a plane with at least two elements.
GDR32 GDR Let n, k \geq1 be natural numbers. Find the number A(n, k) of
GRE34 GRE Notice that in the fraction 16
GRE35 GRE Given a sequence (an), with a1 = 4 and an+1 = a2
GRE36 GRE A regular tetrahedron A1B1C1D1 is inscribed in a regular
HUN38 HUN Prove the following statement: If a polynomial f(x) with
HUN39 HUN A desert expedition camps at the border of the desert, and
HUN40 HUN A polynomial P(x) has degree at most 2k, where k = 0, 1,
HUN41 HUN Prove the following statement: There does not exist a pyramid
HUN42 HUN Let a quadratic polynomial g(x) = ax2 + bx + c be given and
ISR43 ISR Let a, b, c denote the lengths of the sides BC, CA, AB, respec-
ISR45 ISR For any positive integer n we denote by F(n) the number of
NET48 NET In the plane a circle C of unit radius is given. For any line l
NET49 NET Let there be given two sequences of integers fi(1), fi(2), . . .
POL51 POL Let ABC be an arbitrary triangle and let S1, S2, . . . , S7 be
POL52 POL Let a real number \lambda > 1 be given and a sequence (nk) of positive
POL53 POL An infinite increasing sequence of positive integers nj (j =
ROM55 ROM Let a, b be coprime integers. Show that the equation ax2 +
ROM56 ROM Show that for every natural number n, n
ROM57 ROM Let M be a set, and A, B, C given subsets of M. Find a
ROM58 ROM Prove that there exists a natural number k0 such that for
SWE59 SWE Determine the maximum value of x2y2z2w when x, y, z, w \geq0
SWE61 SWE Let a1 \leqa2 \leq\cdot \cdot \cdot \leqan and b1 \leqb2 \leq\cdot \cdot \cdot…
SWE62 SWE T is a given triangle with vertices P1, P2, P3. Consider an arbi-
USA63 USA If a1, a2, . . . , an denote the lengths of the sides of an arbitrary
USA64 USA From point P on arc BC of the circumcircle about triangle
USA65 USA Given f(x) \leqx for all real x and
USS70 USS There are 1979 equilateral triangles: T1, T2, . . . , T1979. A side of
VIE72 VIE Let f(x) be a polynomial with integer coefficients. Prove that
VIE73 VIE In a plane a finite number of equal circles are given. These circles
VIE74 VIE Given an equilateral triangle ABC of side a in a plane, let
VIE75 VIE Given an equilateral triangle ABC, let M be an arbitrary point
VIE76 VIE Suppose that a triangle whose sides are of integer lengths is
YUG77 YUG By h(n), where n is an integer greater than 1, let us denote the
YUG78 YUG By \omega(n), where n is an integer greater than 1, let us denote
YUG79 YUG Let S be a unit circle and K a subset of S consisting of several
YUG81 YUG Let P be the set of rectangular parallelepipeds that have at