已知关于x方程2x^2-mx-2m+1=0的两实数根的平方和等于29/4求m的值
人气:154 ℃ 时间:2019-09-18 02:03:43
解答
楼上计算有误
这是一元二次方程
要保证判别式=m²+8(2m-1)>=0
m²+16m-8>=0
韦达定理
x1+x2=m/2
x1×x2=(1-2m)/2
x1²+x2²=(x1+x2)²-2x1x2
m²/4-(1-2m)=29/4
m²-4+8m-29=0
m²+8m-33=0
(m-3)(m+11)=0
m=3或m=-11
当m=-11时候,判别式
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