分式运算中常见的几种错误现象

• 作 者: 刘家良
• 机 构: 天津市静海县沿庄镇中学,
• 出 处: 数学大世界(初中版)
• 发表日期: 2013年Z2期
• 关键词: 除式 析因 最简公分母 同级运算 求值 原式 加减运算 常数项 整体意识 整式方程

结合实例,列举分式运算中常见的几种错误现象,旨在使学生养成问题思维的严谨性.现象1.字母的取值忽视了分式有意义的条件(分母不为0)例1若分式x~2-9/x-3的值为0,则x=______.误解x=±3.析因当x=-3时,x-3=0.究其根源忽视了x的取值应使分式x~2-9/x-3有意义.正解由x~2-9=0及x-3≠0,得x=-3.现象2.忽视两分式相除中除式不能为0(除式的分

In combination with examples, several common mistakes in fractional computing are listed to help students cultivate the rigor of problem thinking.Physics 1. The value of a letter ignores the condition of fractional significance (the denominator is not zero) Example 1 X = ______ if the fractional x ~ 2-9 / x-3 has a value of 0. Misunderstanding x = ± 3. Factoring When x = -3, x-3 = 0. The root neglects x The value should make the fractional x ~ 2-9 / x-3 meaningful. The positive solution consists of x ~ 2-9 = 0 and x-3 ≠ 0, giving x = -3. Divide the type can not be 0 (except the type of points