A∩R- ≠空集,表明A中的方程有负根.
首先有：delta=(4m)^2-4(2m+6)>=0,即2m^2-m-3>=0,得：(2m-3)(m+1)>=0,即m>=3/2,or m=0,得：m>=-3
两根和=4m>=0,得：m>=0
即在区间m>=3/2,或m=0时为两非负根
相应的,有负根所求的m的范围是：m
已知集合A={x|x2-4mx+2m+6=0,x∈R},若A∩R-≠空集,求实数m的取值范围
已知集合A={x|x2-4mx+2m+6=0,x∈R},若A∩R-≠空集,求实数m的取值范围
数学人气：413 ℃时间：2019-10-17 06:27:51
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