二次函数图形的性质一直是中考的重点和热点,在近几年的各地中考中,结合二次函数图象探究与系数a,b,c相关的不等式,成为新的考查趋势.这类题目在较高层面上去考察学生数形结合的能力,且题目也很灵活,学生碰到往往不知何从下手.其实这类题目还是有规律可循的,大致可分三个步骤来分析.第一步先定a,b,c,Δ的符号a的符号由抛物线的开口方向决定(开口 The nature of the quadratic function graph has always been the focus and hot spot of the senior high school entrance examination. In recent years, it has become a new trend to explore the inequality associated with the coefficients a, b and c in the secondary examinations. At a higher level to examine the ability of students to form a combination of numbers, and the topic is also very flexible, students often do not know where to start. In fact, these topics are still follow the rules, can be roughly divided into three steps to analyze. The sign of the symbol a of a, b, c, Δ is determined by the parabola’s opening direction (the opening