12.040. The height of an isosceles trapezoid is $h$. The upper base of the trapezoid is seen from the midpoint of the lower base at an angle of $2 \alpha$, and the lower base is seen from the midpoint of the upper base at an angle of $2 \beta$. Find the area of the trapezoid in this general case and calculate it without tables if $h=2, \alpha=15^{\circ}, \beta=75^{\circ}$.