複選題11. Let A be the region bounded above by the graph of y = sin(πx) and below by the graph of y = x3 - 4x. (A)(2.1,0.8) falls into the region A. (B) The area of A can be represented bydx. (C) The area of A is equal to 4. (D)The region A is the base of a solid. For this solid, each cross section per- pendicular to the a-axis is a square.The volume of this solid is equal to dx. (E)The region A models the surface of a small pond. At all points in A tance :i from the y-axis, the depth of the water is given by h(x) = 3-x. The yolume of water in the pond is equal todx.