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一、用判别式解题时不可忽视二次项系数不为零例l若关于x的方程m2x2+(2m+1)x+1=0有两个实数根,求m的取值范围.错解:∵方程有两个实数根.∴△=(2m+1)2-4m2≥0,解得m≥
First, with the discriminant solution to the problem can not be ignored when the quadratic coefficient is not zero Example l If the equation on x m2x2 + (2m +1) x +1 = 0 has two real roots, find the range of m. : ∵ The equation has two real roots .∴ △ = (2m + 1) 2-4m2≥0, so that m≥