The solution in △ADE (1), y2=x2+AE2-2x? AE？ cos60？ y2=x2+AE2-x？ AE，①

s△ade = 12s△ABC = 32 = 12x？ AE？ sin60？ x？ AE=2。 ②

② Substitute into ① to get y2 = x2+(2x) 2-2 (y > 0),

∴y=x2+4x2？ 2( 1≤x≤2)；

(2) If DE is water pipe y=x2+4x2? 2≥2? 2? 2=2,

"=" holds if and only if x2=4x2, that is, x=2, so DE∑BC, and DE=