MEMO 2017 ekipno problem 5
Kvaliteta:
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Avg: 6,0Let be an acute-angled triangle with
and circumcircle
. Let
be the midpoint of the shorter arc
of
, and let
be the intersection of the rays
and
. Let
be the intersection of the internal bisector of the angle
and the circumcircle of the triangle
. Let us assume that
is inside the triangle
and there is an intersection
of the line
and the circle
such that
is the midpoint of the segment
.
Show that is the midpoint of the segment
, where
and
are the excentres of
opposite to
and
, respectively.
Izvor: Srednjoeuropska matematička olimpijada 2017, ekipno natjecanje, problem 5