题目

如图所示，菱形的边长为6厘米，．从初始时刻开始，点、同时从点出发，点以1厘米/秒的速度沿的方向运动，点以2厘米/秒的速度沿的方向运动，当点运动到点时，、两点同时停止运动，设、运动的时间为秒时，与重叠部分的面积为平方厘米（这里规定：点和线段是面积为0的三角形），解答下列问题： （1）点、从出发到相遇所用时间是         秒； （2）点、从开始运动到停止的过程中，当是等边三角形时的值是        秒； （3）当0≤≤6时，求与之间的函数关系式． 答案：（1）6．······················································································································· 3分 （2）8．······················································································································· 3分 （3）①当0时， ． ·········································· 3分 ②当3时， =········································································································· 3分

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