解答:解:(1)如图所示:点D的坐标是(0,5);点E的坐标是(-2,0);
(2)如图所示:(6,-3),
△A1B1C1的面积为:△ABC的面积=3×5-
×1×3-1 2
×2×5-1 2
×2×3=5.5;1 2
(3)∵OA=
=3
62+32
,
5
CO=
=5,
32+42
∴(2)中线段AC扫过的面积为:大扇形AOA1的面积-小扇形COC1的面积=
=5π.90π[(3
)2?52]
5
360
故答案为:(0,5),(-2,0);(6,-3),5.5;5π.