摘要：25．如图.将含角的直角三角板()绕其直角顶点逆时针旋转解().得到.与相交于点.过点作交于点.连结．设.的面积为.的面积为． (1)求证:是直角三角形, (2)试求用表示的函数关系式.并写出的取值范围, (3)以点为圆心.为半径作. ①当直线与相切时.试探求与之间的关系, ②当时.试判断直线与的位置关系.并说明理由． 25． (1). 又.································································· 1分 又.···························································· 2分 . .即是直角三角形,······························································ 3分 (2)在中.. . .. ,··············································································· 4分 ,··························· 5分 (3)①直线与相切时.则． . ． .································································· 6分 又. 是等边三角形.. . 又,······································································ 7分 ②当时. 则有.解之得或,··················································· 8分 (i)当时.. 在中... 在中..········································· 9分 .即. 直线与相离,···························································································· 10分 (ii)当时. 同理可求出:.·············································· 11分 . 直线与相交．···························································································· 12分

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