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在一元二次方程ax~2+bx+c=0(a≠0)中,△=b~2-4ac叫做这个方程根的判别式.这个式子看似简单,其实应用十分广泛,它不仅能解决一元二次方程根的个数问题,而且还能解决二次函数的某些问题.在中考中,判别式有以下五个方面的应用.一、确定方程根的个数例1(2010年黄冈卷)甲乙两同学投掷一枚骰子,用字母p,q分别表示两人各投掷一次的点数.
In the quadratic equation ax ~ 2 + bx + c = 0 (a ≠ 0), △ = b ~ 2-4ac is called the discriminant of this equation root. This formula seems simple, in fact, a wide range of applications, it not only Can solve the problem of the number of roots of a quadratic equation, but also solve some problems of the quadratic function.In the test, the discriminant has the following five aspects of application. First, determine the number of root equation Example 1 (2010 Year Huanggang volume) A class two students throwing a dice, with the letters p, q, respectively, each of the two throwing points.