设x＋y=t
由x ＋2xy－1＝0,得y=（1-x）/2x
t=x+（1-x）/2x
2x²-（2t+1）x+1=0
△=（-（2t+1））²-8＞=0
2t+1＞=2根号2,t＞=（2根号2-1）/2
2t+1＜=-2根号2,t＜=（-2根号2-1）/2
x＋y的取值范围是（-∞,（-2根号2-1）/2】∪【（2根号2-1）/2,+∞）
.设实数x、y满足x ＋2xy－1＝0,则x＋y的取值范围是
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