Suppose a curve is traced by the parametric equations $$x = 2 \big(\sin(t)+\cos(t)\big)$$
$$y = 20 - 4\cos^2(t) - 8 \sin(t)$$
as $t$ runs from $0$ to $\pi$. At what point $(x,y)$ on this curve is the tangent line horizontal?
$x =$
$y =$