Assuming you mean
over the domain

we first observe that
for all
on the coordinate axes.
There are no critical points elsewhere in the interior of
, since


Parameterize the circular arc boundary by
and
, where
. Then

Find the critical points of
.





In the first case, we get

where
is an integer; the only solution on the boundary of
is
corresponding to the point
.
In the second case, we get

with only one relevant solution at
corresponding to
.
In the third case, we get

but there is no
in this family of solutions such that
.
So, we find

(but really any point on either axis works)
