一元二次方程根的判别式深刻揭示了根与系数之间内在联系,常用来判断方程有无实根,反过来,当一个一元二次方程有实根时,我们又可利用b2-4ac≥0来巧妙解题,达到出奇制胜的效果,为了帮助同学们学好用好根的判别式,下面就根的判别式的逆用略举几例. The discriminant of the root of the quadratic equation reveals the intrinsic relationship between the root and the coefficient. It is often used to judge whether the equation has real roots. Conversely, when a quadratic equation has a real root, we can use b2-4ac≥ 0 to solve problems ingeniously to achieve the effect of surprising victory, in order to help students learn to use the root of the discriminant, the root of the discriminant against the use of a few examples.