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.
?
vertices, each edge has one of the colors 
, 
, or 
. For each 
, if the vertices can be divided into 
groups such that any two vertices connected by an edge of color 
are in different groups, find the minimum possible value of 
.
such that, for all 
,
such that for all integer 
and a subset 
of ![$[n],$](http://latex.artofproblemsolving.com/d/2/7/d27d2715f4f95c24a28b7c6371a006d4c803b2cf.png)
satisfy 
for all 
then 
+1 w
be the set of positive integers. Find all functions 
such that for all 
, ![\[m^2f(m) + n^2f(n) + 3mn(m + n)\]](http://latex.artofproblemsolving.com/0/f/f/0ff783fa217b7be4bda5006e417f1471ea3a6fca.png)
is a perfect cube.
![$\mathbb{R}[x]$](http://latex.artofproblemsolving.com/a/8/8/a88b9f4858016b1771635c611d44b56161a08009.png)
be the set of all polynomials with real coefficients. Find all functions ![$f: \mathbb{R}[x] \rightarrow \mathbb{R}[x]$](http://latex.artofproblemsolving.com/0/3/3/033be3ab043bd47e537f01791c813739ad5c7da5.png)
satisfying the following conditions:
maps the zero polynomial to itself,![$P \in \mathbb{R}[x]$](http://latex.artofproblemsolving.com/f/7/c/f7c4c970908aa5570a9afcc45fc16c1d36cc3d5d.png)
, 
, and![$P, Q \in \mathbb{R}[x]$](http://latex.artofproblemsolving.com/c/3/0/c301578bade5b93056d77454921cba0a9812212c.png)
, the polynomials 
and 
have the same set of real roots.
be a square of center 
and let 
be the symmetric of the point 
with respect to point 
. Let 
be the intersection of 
and 
, and let be the intersection of 
and 
. Show that 
is the angle bisector of 
.
be reals such that 
Show that
Let 
and Show that
be a polygon formed by the edges of an infinite chessboard, which does not intersect itself. Let the numbers 
represent the number of unit squares that have exactly 
edges on the boundary of respectively. Find the largest real number 
such that the inequality 
holds for each polygon constructed with these conditions.
and 
with real coefficients satisfying
be a cyclic quadrilateral. Points and 
lie on the sides 
and 
in such a way that 
and 
. Let be the midpoint of 
. Prove that 
.
be the reflection of with respect to . The quadrilateral 
will be a parallelogram, then the triangle 
will be congruent to the triangle 
, from here we get that 
. Therefore, 
is an isoscele triangle, and since is the median, it will also be the height.
intersects 
at 
.
and 
are isoscele triangles. Let and 
be the midpoints of 
and 
.
is similar to 
and take 
such that these triangles are similar to 
that sends 
to 
. Thus there exists a spiral similarity with center that sends 
to 
hence 
. Similarly 
is rhomboid 
,
be the point such that 
is a parallelogram. A bit of angle chasing (computing angles at combined with the fact that 
and 
are isosceles) yields 
. This means is the circumcenter of 
and the perpendicular bisectors of 
and 
are perpendicular. But these bisectors are precisely 
and , respectively. The end.
Prove that
and 
.
and 
Find the value range of 
