题目

已知梯形中，于于相交于的中点(1)若点为线段上一点，且过点作于试证：(2)求证：  答案：(1)∵为中点，      ∴      又∵且      ∴      ∴在和中，      ∴ ······································3分      ∴      又∵      ∴      即：··········································4分    又∵     ∴连接∵∴为的角平分线  ∵∴ ·················································5分(2)过作交的延长线于      ∵梯形中，   ∴      又∵      ∴四边形为，  ∴ ·················6分      ∵ 又且      ∴      ∴为等腰直角三角形      又∵ ∴      ∴      ∴ ·············································7分      ∵      ∴      ∵      ∴在和中      ∴ ···············································9分      ∴      ∵    ∴···············································10分 解析:略 

查看本题答案和解析