As shown in the figure, in ladder ABCD, ad ‖ BC, ad = 2, BC = 4, point m is the midpoint of AD, and △ MBC is an equilateral triangle (1) Prove: the trapezoid ABCD is isosceles trapezoid; (2) the moving points P and Q move on the line BC and MC respectively, and ∠ MPQ = 60 ° remains unchanged. Let PC = x, MQ = y, find the functional relationship between Y and X; (3) in (2): when the moving points P and Q move to where, the quadrilateral with points P, m and two points in points a, B, C and D as the vertex is a parallelogram? It also points out the number of parallelograms that meet the conditions. ② when y is the minimum, the shape of △ PQC is judged and the reason is given

As shown in the figure, in ladder ABCD, ad ‖ BC, ad = 2, BC = 4, point m is the midpoint of AD, and △ MBC is an equilateral triangle (1) Prove: the trapezoid ABCD is isosceles trapezoid; (2) the moving points P and Q move on the line BC and MC respectively, and ∠ MPQ = 60 ° remains unchanged. Let PC = x, MQ = y, find the functional relationship between Y and X; (3) in (2): when the moving points P and Q move to where, the quadrilateral with points P, m and two points in points a, B, C and D as the vertex is a parallelogram? It also points out the number of parallelograms that meet the conditions. ② when y is the minimum, the shape of △ PQC is judged and the reason is given

(1) It is proved that: ∵ MBC is an equilateral triangle, ∵ MB = MC, ∵ MBC = ∵ MCB = 60 °. ∵ m is the midpoint of AD, ∵ am = MD. ∵ ad ∥ BC, ∵ AMB = ∵ MBC = 60 °,