关于x2y2x2y2的百科

• 已知实数x,y满足(x2+y2)(x2+y2-1)=2,则x2+y2=

• 问题详情：已知实数x,y满足(x2+y2)(x2+y2-1)=2,则x2+y2=________.【回答】.2  解:∵(x2+y2)(x2+y2-1)=2,∴(x2+y2)2-(x2+y2)-2=0,∴(x2+y2-2)(x2+y2+1)=0,∴x2+y2=2或x2+y2=-1,∵x2+y2=-1(舍去),故x2+y2=2,点拨:此题应用换元法,将x2+y2≥0,而将其负值也取上的错误.知识点...
• 2021-07-1713988