As shown in the figure, in the triangle ABC, the angle a is greater than 90 degrees, BD and CE are the heights of the triangle respectively, and M is the midpoint of the edge BC, connecting De, DM and em (1) Proof: Triangle MDE is isosceles triangle (2) Try to explore: whether the triangle MDE can become a right triangle, if possible, request the BAC degree of this angle, if not, please briefly explain the reason

As shown in the figure, in the triangle ABC, the angle a is greater than 90 degrees, BD and CE are the heights of the triangle respectively, and M is the midpoint of the edge BC, connecting De, DM and em (1) Proof: Triangle MDE is isosceles triangle (2) Try to explore: whether the triangle MDE can become a right triangle, if possible, request the BAC degree of this angle, if not, please briefly explain the reason

1. In ⊙ BD ⊥ Ca, CE ⊥ ab ⊥ RT ⊥ BDC and RT ⊥ BEC, M is the middle point on the common hypotenuse, then: DM = 1 / 2BC, EM = 1 / 2BC (using the hypotenuse center line of right triangle = 1 / 2 hypotenuse) ⊥ DM = EM ⊥ MDE is isosceles triangle 2, ⊥ MDB is isosceles triangle ⊥ to make ⊥ MDB a right triangle, then ⊥ MDB is