k为何值时,不等式-3<[x2+kx+2]/[x2-x+1]</=2对任意实数恒成立
回复(1) 2010-04-18 20:33 来自版块 - 
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teacher2解答:-3<(x^2+kx+2)/(x^2-x+1) 3+(x^2+kx+2)/(x^2-x+1) =[4x^2+(k-3)x+5]/(x^2-x+1)>0 因为x^2-x+1=(x-1/2)^2+3/4>0 所以4x^2+(k-3)x+5>0 ...(2010-04-18 20:38)

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