Κυριακή 9 Ιουνίου 2013

▪ Bosnia Herzegovina Team Selection Test 2013

Ημέρα 1η
1. Triangle is right angled at . Lines and are internal angle bisectors.  and intersect altitude at points and respectively. Prove that the line which passes through the midpoints of segments and is parallel to .
Κάντε κλικ εδώ, για να δείτε τη λύση της άσκησης, που μου έστειλε ο Νίκος Φραγκάκης, από την Ιεράπετρα.
2. The sequence is defined by
  and .
Prove that all terms of this sequence are perfect squares. 

3. Prove that in the set consisting of people we can find a group of people in which everyone knows everyone or noone knows noone. 
Ημέρα 2η
4/ Find all primes such that divides and divides
5/ Let be nonnegative real numbers of sum equal to . Let 
.
Find:
a) ;
b) ;
c)
6. In triangle , is the incenter. We have chosen points on segments respectively such that .
Prove that the points and belong to Euler line of triangle where is circumcenter of .

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