本文通过关于恒成立问题教学的一个案例,展示学生在解决恒成立问题时出现的常见错误.通过错误原因分析及纠正,使学生在恒成立问题的求解中,对变量的关注及分析更准确到位,同时也是对学生及教师共同纠错的教学方式的探究. This article through a case of teaching on the issue of constant establishment, to show students common errors in the solution to the problem of permanent establishment.Through the analysis and correction of the causes of errors, so that students in the establishment of a constant problem, the variable attention and analysis more accurate , But also for students and teachers to explore ways of teaching error correction.