∠∠BCD+∠ACO = 90,∠AC0+∠OAC=90,
∴∠BCD=∠CAO,
∠∠BDC =∠COA = 90,CB=AC,
In δ△BDC and δ△COA,
∠BCD=∠CAO∠BDC=∠COA=90 BC=AC,
∴△BDC≌△COA(AAS),
∫ The linear function y=-2x+2 intersects the Y axis at point A and the X axis at point C,
∴ The coordinates of point A are (0,2), and the coordinates of point C are (1, 0).
∴BD=OC= 1,CD=OA=2,
∴ The coordinate of point B is (3,1);
(2) In Rt△AOB, OA= 1, OB=2, and from Pythagorean theorem, AB = 5.
∴S△ABC= 12AB2=52.
Let the analytical formula of BC line be y=kx+b, ∫ b (0,2), c (3, 1),
∴b=23k+b= 1,
The solution is k=- 13, b=2,
∴y=- 13x+2.
Similarly, the analytical formula of straight line AC is: y = 12x- 12.
As shown in the answer sheet 1,
Let the straight line L intersect BC and AC at points E and F respectively, then ef = (-13x+2)-(12x-12) =1