25．如图1.正方形和正三角形的边长都为1.点分别在线段上滑动.设点到的距离为.到的距离为.记为(当点分别与重合时.记)． (1)当时.求的值, (2)当为何值时.点落在对角形上?请说出你的理由.——青夏教育精英家教网—

25．如图1.正方形和正三角形的边长都为1.点分别在线段上滑动.设点到的距离为.到的距离为.记为(当点分别与重合时.记)． (1)当时.求的值, (2)当为何值时.点落在对角形上?请说出你的理由.并求出此时的值, (3)请你补充完成下表: 0.03 0 0.29 0.29 0.13 0.03 (4)若将“点分别在线段上滑动改为“点分别在正方形边上滑动．当滑动一周时.请使用(3)的结果.在图4中描出部分点后.勾画出点运动所形成的大致图形． (参考数据:．) 25．解:(1)过作于交于.于． .. .．······················································································ 2分 .．························································································· 3分 (2)当时.点在对角线上.其理由是:·········································· 4分过作交于. 过作交于．平分..． ..． .． .．即时.点落在对角线上．································································ 6分 (以下给出两种求的解法) 方法一:.．在中.. ．·········································································· 7分．························································································ 8分方法二:当点在对角线上时.有 .··························································································· 7分解得．························································································ 8分 (3) 0.13 0.03 0 0.03 0.13 0.29 0.50 0.50 0.29 0.13 0.03 0 0.03 0.13 ································································ 10分 (4)由点所得到的大致图形如图所示: ··························································································· 12分说明:1．第(2)问回答正确的得1分.证明正确的得2分.求出的值各得1分, 【查看更多】

题目列表(包括答案和解析)

正在江西南昌举行的全国第七届城市运动会共有10350人参加决赛阶段的比赛，10350用科学记数法表示应为（　　）

A．10.35×10³

B．1.035×10⁴

C．0.1035×10⁵

D．1035×10

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（2011江西南昌，4，3分）下列运算正确的是（）.

A.a+b=ab B.a2·a3=a5 C.a2+2ab－b2=(a－b)2 D.3a－2a=1

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（2011江西南昌，12，3分）方程组的解是 .