设实数x，y满足x2+2xy-1=0，则x+y的取值范围是____．

设实数x，y满足x2+2xy-1=0，则x+y的取值范围是____．
【正确答案】：(一∞，一1]∪[1，+∞)。解析：由题意得x2+2xy+y2=y2+1≥1，(x+y)2≥1，x+y≥1或x+y≤一1．