如图,已知矩形ABCD中,AB=4cm,AD=10cm,点P在边BC上移动,点E,F,G,H...答:(1)∵点E,F,G,H分别是AB,AP,DP,DC的中点 ∴⊿AEF∽ABP,⊿DGH∽⊿DPC ∴EF/BP=AE/AB=1/2,EF=1/2BP GH/PC=DH/DC=1/2,GH=1/2PC ∴EF+GH=1/2(BP+PC)=1/2BC=5cm (2)据上可知:EF/GH=BP/PC 过P作PQ⊥AD,交AD于Q ∴AQ=BP,QD=PC,EF/GH=AQ/QD ∵角APD=90...
如图,在平面直角坐标系中,已知矩形ABCD的三个顶点B(4,0)、C(8,0...答:显然A(4, 8)过A: 8 = 16a + 4b, 4a + b = 2 (1)过C: 0 = 64a + 8b, 8a + b = 0 (2)由(1)(2): a = -1/2, b = 4 y = -x²/2 + 4x AC的方程: (y - 0)/(x - 8) = (8 - 0)/(4 - 8)y = 16 - 2x t秒时, AP = t, P(4, 8-t),...