由y=x2-1x2+1，得x2=y+11-y．
∵x2≥0，∴y+11-y≥0，解得-1≤y＜1．
故答案为：[-1，1）．
关系数据醋的数据结构是怎样的？它对关系有什么要求？
Be careful! There's some broken glass on the ground. The underlined part means " ______ ". [ ]
A. Look out
B. Go ahead
C. Get ready
D. Keep quiet
