MEMO 2007 ekipno problem 7
Kvaliteta:
Avg: 2,3Težina:
Avg: 6,0 A tetrahedron is called a MEMO-tetrahedron if all six sidelengths are different positive integers where one of them is
and one of them is
. Let
be the sum of the sidelengths of the tetrahedron
.
(a) Find all positive integers
so that there exists a MEMO-Tetrahedron
with
.
(b) How many pairwise non-congruent MEMO-tetrahedrons
satisfying
exist? Two tetrahedrons are said to be non-congruent if one cannot be obtained from the other by a composition of reflections in planes, translations and rotations. (It is not neccessary to prove that the tetrahedrons are not degenerate, i.e. that they have a positive volume).
and one of them is
. Let
be the sum of the sidelengths of the tetrahedron
. (a) Find all positive integers
so that there exists a MEMO-Tetrahedron
with
. (b) How many pairwise non-congruent MEMO-tetrahedrons
satisfying
exist? Two tetrahedrons are said to be non-congruent if one cannot be obtained from the other by a composition of reflections in planes, translations and rotations. (It is not neccessary to prove that the tetrahedrons are not degenerate, i.e. that they have a positive volume). Izvor: Srednjoeuropska matematička olimpijada 2007, ekipno natjecanje, problem 7
Školjka