已知实数x、y满足(x2+y2)(x2+y2-1)=2,则x2+y2的值为_.
问题描述:
已知实数x、y满足(x2+y2)(x2+y2-1)=2,则x2+y2的值为______.
答
令x2+y2=t,原方程变形为,t(t-1)=2,
整理得,(t-2)(t+1)=0,
解得t1=2,t2=-1,
∵x2+y2≥0,∴x2+y2=2.
故答案为2.