Y by
Let
be the circumcircle of triangle
, and let
be a midpoint of arc
, not containing
. The incircle of
is centered at
and touches BC at
. The
-excircle of
is centered at
and touches
at
. Lines
and
are drawn intersecting
again at points
and
, respectively. Let
intersect
at
. Show that
, and
are collinear.






















