AoPS Academy
[/quote]
, do not answer with "
is a solution" only. Either you post any kind of proof or at least something unexpected (like "
is the smallest solution). Someone that does not see that is a solution of the above without your post is completely wrong here, this is an IMO-level forum.
with 
and 
.
?
of positive integers such that
be a circle inscribed inside a rhombus 
. Let 
and 
be variable points on 
and 
respectively, such as 
is always the tangent line to . and the area of triangle 
is the same.
, find the smallest integer 
such that any graph with 
vertices and at least edges must contain at least two disjoint cycles (cycles with no common vertices).
passing through point 
is an oblique strophoid. be a cyclic quadrilateral for which 
. Construct two squares 
and 
externally on the sides 
and 
respectively.
meets 
at 
, 
meets 
at 
and 
denotes circumcenter of . Prove that 
and 
meets again on 
.
be an acute triangle and let 
be the foot of the -bisector. Moreover, let 
be the midpoint of . The circle 
with diameter 
meets 
at 
, while the circle 
with diameter meets 
at 
. Assume that and lie inside . Prove that 
, , , 
are concyclic.
of degree 
having 
distinct real roots (
), such that for every root 
: 
.
defined on all real numbers and taking real values such that ![\[f(f(y)) + f(x - y) = f(xf(y) - x),\]](http://latex.artofproblemsolving.com/f/5/2/f528fc4047e21247663d4993913eadf346315be7.png)
for all real numbers 
. Prove that there does not exist a pair of rational numbers 
such that 
.
![$P\in \mathbb{R}[x]$](http://latex.artofproblemsolving.com/7/4/c/74cb2247069abb8a22666e87fcbd69a55a015004.png)
for which there exists 
such that for all 
we have: ![\[P\left(x+\frac1n\right)+P\left(x-\frac1n\right)=2P(x).\]](http://latex.artofproblemsolving.com/9/0/9/90954cdeade9d13149e1aaa03df2c87dff157041.png)
and 
, prove that there exists a positive integer and a set 
of at least multiples of such that the numbers 
are odd for every 
. 
is the sum of all positive integers of 
(1 and included).
and , prove that there exists a positive integer and a set of at least multiples of such that the numbers are odd for every . is the sum of all positive integers of (1 and included).
where 
are all odd prime factors of and 
is 
if 
is odd and 0 otherwise. Now we will build our set with terms of the form 
where 
and 
are unknwons and 
.
is even so 
is odd . Hence 
where is the product of 
, divisors of 
. From our previous observation , is odd. odd perfect squares 
with 
. Then 
is also odd , from a similar reason as above.
and 
work (Note that we can pick large enough to make positive)
which is a positive integer from Euler's Theorem and it's also odd since every term is odd.
![\[
\text{Find all prime numbers } (p, q) \text{ such that } p^2 + 3pq + q^2 \text{ is a fifth power of an integer.}
\]](http://latex.artofproblemsolving.com/c/f/8/cf855cb087102024a50d41f49c67e7fd1ef22767.png)
