and 
Prove that
Let 
and 
Prove that
prove that![\[ \frac{a^2}{b^2} + \frac{b^2}{c^2} + \frac{c^2}{d^2} + \frac{d^2}{a^2}\geq\frac{a}{d} + \frac{b}{a} + \frac{c}{b} + \frac{d}{c}\]](http://latex.artofproblemsolving.com/0/0/4/004e7f148bbb0c797688f5195aa4002dbc316470.png)
If you know same tasks, link them please
.
,
,
are concurrent and the point of concurrence is 
,
(
well). i want to study so if you guys have some easy or normal problems please send me
Y by
In the cyclic quadrilateral 
, the diagonals 
and 
intersect at 
. Let 
be the center of the circumcircle , and 
a point of the extension of 
beyond 
. A parallel line to 
is drawn through that cuts the extension of 
beyonf 
at 
. Let 
be a point interior to , such that 
and 
. Prove that 
.
, the diagonals 
and 
intersect at 
. Let 
be the center of the circumcircle , and 
a point of the extension of 
beyond 
. A parallel line to 
is drawn through that cuts the extension of 
beyonf 
at 
. Let 
be a point interior to , such that 
and 
. Prove that 
.
