已知对于任意实数x,kx的2次方减2x加k恒为正数,求实数k的取值范围
人气:114 ℃ 时间:2019-10-17 05:16:27
解答
设y=kx²-2x+k
因为对于任意实数x ,y恒为正数
所以抛物线y=kx²-2x+k的开口向上,并切与x轴没有交点
可得k>0
(-2)²-4k²<0
解得k>1
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