AD垂直于BD,CD设D坐标为(x,y)AD=(x+2,y-6)BD=(x+2,y-1)CD=(x-4,y-4)(x+2)(x+2)+(y-6)(y-1)=0(x+2)(x-4)+(y-6)*(y-4)解方程组即可
解: BC:X-2Y+4=0 斜率:1/2 ∵AD垂直于BC ∴AD的斜率为-2,方程为:2X+Y-2=0 连立求解,得 X=0 Y=2 即:D(0,2)