[/quote]
,
and 
,
as follows:
where 
are all the positive divisors of 
.
Find all positive integers 
.
Find all positive integers 
.
be a convex quadrilateral. Suppose that the circles with diameters 
and 
intersect at points 
and 
.
and 
.
,
attaining all positive values and positive numbers 
are given. Numbers 
satisfy
for every 
.
.
?
be reals such that 
and 
.
and 
points on a plane is 
,
such that: in every set of 
points of a plane, no three of which are collinear, consisting of 
consisting of 
disting positive integers smaller than 
are given. Prove that there exists a positive integer 
that can be written in the form 
,
in at least 
different ways.
,
be the set of all positive integers not exceeding ![\[
P_n(x) = \sum_{k \in S_n} x^{k - 1}
\]](http://latex.artofproblemsolving.com/3/a/c/3ac60cb70baf4dfcf297e9af87480a8ee34ba70c.png)
and a polynomial 
with integer coefficients such that![\[
P_n(x) = (x^{r_n} + 1) Q_n(x).
\]](http://latex.artofproblemsolving.com/7/0/e/70e19a9d3e0a7e97abc7aa08d3f23126c14ea7d0.png)
is irreducible in ![$\mathbb{Z}[x]$](http://latex.artofproblemsolving.com/4/b/7/4b7d768fffbb7a1a6163af392ed348f2d49d8783.png)
.
integers are such that 
is prime and 
.
such that 
.
board, each square is colored either white or black, with all the squares on the border of the board being black. Additionally, no 
square within the board has all four squares of the same color. Prove that the board contains a 
Y by Adventure10, Mango247
Let the 
be a regular prism. The points 
and 
are the midpoints of the sides 
, respectively 
, and the angle between the lines 
and 
is of 
. Let 
and 
be the intersection of the lines 
and 
, with respectively 
and 
.
a) Prove that
;
b) Find the measure of the angle between the line
and the plane 
.
Mircea Fianu
be a regular prism. The points 
and 
are the midpoints of the sides 
, respectively 
, and the angle between the lines 
and 
is of 
. Let 
and 
be the intersection of the lines 
and 
, with respectively 
and 
.a) Prove that
;b) Find the measure of the angle between the line
and the plane 
.Mircea Fianu
