若|x|³-2x²+1<0则x的取值范围是_ 20
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|x|³-2|x|²+1<0
|x|³-|x|²-|x|²+|x|-|x|+1<0
|x|²(|x|-1)-|x|(|x|-1)-(|x|-1)<0
(|x|-1)(|x|²-|x|-1)<0
(|x|-1)[(|x|-½)²-5/4)<0
(|x|-1)[|x|-(1+√5)/2][|x|+(√5-1)/2]<0
|x|+(√5-1)/2恒>0,因此
(|x|-1)[|x|-(1+√5)/2]<0
1<|x|<(1+√5)/2
-(1+√5)/2<x<-1或1<x<(1+√5)/2
不等式的解集为(-(1+√5)/2,-1)U(1,(1+√5)/2)
|x|³-|x|²-|x|²+|x|-|x|+1<0
|x|²(|x|-1)-|x|(|x|-1)-(|x|-1)<0
(|x|-1)(|x|²-|x|-1)<0
(|x|-1)[(|x|-½)²-5/4)<0
(|x|-1)[|x|-(1+√5)/2][|x|+(√5-1)/2]<0
|x|+(√5-1)/2恒>0,因此
(|x|-1)[|x|-(1+√5)/2]<0
1<|x|<(1+√5)/2
-(1+√5)/2<x<-1或1<x<(1+√5)/2
不等式的解集为(-(1+√5)/2,-1)U(1,(1+√5)/2)
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