Τρίτη 22 Μαΐου 2012

▪ Kazakhstan National Mathematical Olympiad 2012

Ημέρα 1η
1. Solve the equation
   
in prime numbers. 
2. Given two circles and with centers and that intersect at the points and .Passes through A two lines that intersect the circle at the points and , and the circle at the points and (points in colinear). Denote the midpoints of the segments and , through and .Prove that:
Points and lie on a circle
The center of the circle passing through and lies in the middle of the segment
3. Let for which the following conditions::
Find the minimum of expression .
Ημέρα 2η
1. Do there exist a infinite sequence of positive integers ,such that for any the relation ? .
2. Given an inscribed quadrilateral , which marked the midpoints of the points in this order. Let diagonals and intersect at point . Prove that the triangle have the same radius of the circles.
3. The cell of a board are painted in two colors - white and black. The unit cell of a row (column) is called dominant on the row (the column) if more than half of the cells that row (column) have the same color as this cell. Prove that at least cells on the board are dominant in both their row and column. 
Grade 10
Ημέρα 1η
1. For a positive reals prove inequlity:
.
2. Let be an inscribed quadrilateral, in which . On the rays and are selected points and , respectively, such that. Let - the midpoint of .Prove that if ,so .
3. There are balls numbered from to , and boxes numbered from to . For each , ball number can only be put in the boxes with numbers from to . Let be an integer from to . In how many ways we can choose balls, boxes and put these balls in the selected boxes so that each box has exactly one ball? 
Ημέρα 2η
1. Let -Excircles triangle with area . touch side at the point Direct intersect at the points and .Let - area of ​​the quadrilateral Similarly, we define . Prove that
  .
2. Function such that for any are real numbers. Prove that for all real numbers
3. The sequence defined as follows: and for any true equalities
Find the smallest such that divided
Grade 11
Ημέρα 1η
1. The number , with digits , is a prime. Prove that
2. We call a table consisting of zeros and ones right if the sum of the numbers in each row and each column is equal to . Two right tables are called similar if one can get from one to the other by successive interchanges of rows and columns. Find the largest possible size of a set of pairwise similar right tables. 
3. Line is tangent to the incircle of triangle in such a way that the points and lie on the sides and , respectively. On the sides and are selected points and , respectively, so that and . Prove that all lines constructed in this manner pass through one point 
Ημέρα 2η
1. Function such that for any are real numbers. Prove that for all real numbers
2. Given the rays and .Inside the smaller angle selected points and , such that and The circle, which concern the rays and , intersects the second circle, which concern the rays and at the points and . Prove that
3. Consider the equation , where are fixed rational numbers. Prove that either such an equation has no solutions in rational numbers, or it has infinitely many solutions.
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