Trigonometry of Trapeziums!

$\large{ \left \lfloor \left( 3 + \tan^2(x) \right) \left(\dfrac{\tan(y)}{\tan(x)} \right) + \left( \dfrac{2\sin(x) + \sin(3x)}{2\cos(x) + \cos(3x)} \right) \left( \cot(z) \right) \right \rfloor = \ ?}$

Let $ABCD$ be a trapezium with $AB \parallel CD$ for which $AD=CD$ and $AC=BC$ and let $E$ be the intersection of $AC$ and $BD$ . Let $x,y,z$ denote the measure of the angles of $ABC, BDC, AED$ respectively. If $y \leq 30^\circ$ , find the value of the expression above.