大家都知道,二次方程ax~2+bx+c=0…①的根与判别式△=b~2-4ac的关系:△0圳①有两个不等实根;△=0圳①有两个相等实根;△0圳①没有实根.“运用之妙,存乎一心”.判别式看似简单,实在神通广大,请看数例:例1已知ba+ca=1,求证:b2+4ac≥0.分析已知式可整理为a-b-c=0,由此可知方程ax As we all know, the relationship between the root of the quadratic equation ax~2+bx+c=0...1 and the discriminant △=b~2-4ac: △0 Shenzhen has two unequal real roots; △=0 Shenzhen 1 There are two equal real roots; △0 zhen 1 has no real roots. “The use of the wonderful, keep in mind.” Discriminant seems simple, it is supernatural, see a few examples: Example 1 is known ba+ca=1, Proof: b2+4ac ≥ 0. Analysis of known formula can be organized as abc = 0, from which we can see the equation ax