“函数log_■(x~2+4x+4)在什么区间上是增函数?”这是八四年全国高等学校招生统一考试中的一道数学试题,它引起了中学数学教师的注意。现把我们对复合函数增减区间复习的体会写出来,供大家参考。函数y=kx+b(k≠0),y=ax~2+bx+c(a≠0)的增减区间的求法,初中学生已掌握,函数 “What function log_ ■ (x ~ 2 + 4x + 4) is an increasing function in what interval?” This is a math test in the Unified National Examination for Higher Education for Nationalities in 1984, which attracted the attention of middle school mathematics teachers. Now we have to write down the experience of the compound function to increase or decrease range for your reference. Function y = kx + b (k ≠ 0), y = ax ~ 2 + bx + c (a ≠ 0) increase and decrease of the interval of the method, junior high school students have mastered, the function