近年来 ,三次函数频频成为热点考点之一 :2 0 0 0年全国高考 (春季 )出了一题三次函数图象的选择题 ;2 0 0 1年“希望杯”(高二 )数学竞赛 ;2 0 0 2年全国高中数学竞赛都考了三次函数的最值问题 .由于一般的三次函数在中学数学里没有专门研究 ,而全国级的三大考试 .似乎对超出 In recent years, the three functions have become one of the hotspots. In the year of 2000, the national college entrance examination (spring) produced a multiple-choice question for the three-time function image; the “Hope Cup” (Senior Year Two) Mathematics Competition in 2010; 2 In the twentieth year of the National High School Mathematics Competition, the question of the value of the three functions was examined. Since the general three-order function has not been specifically studied in the middle school mathematics, the national three major examinations seem to exceed the