• 设x=a2b2+5,y=2ab-a2-4a,若x>y,则实数a、b满足的条件是 .试题及答案-填空题-云返教育

    • 试题详情

      设x=a2b2+5,y=2ab-a2-4a,若x>y,则实数a、b满足的条件是         

      试题解答


      ab≠1或a≠-2
      解:由x-y=a2b2+5-2ab+a2+4a
      =(a
      2b2-2ab+1)+(a2+4a+4)
      =(ab-1)
      2+(a+2)2
      ∵x>y,∴(ab-1)
      2+(a+2)2>0.
      则ab-1≠0或a+2≠0,即ab≠1或a≠-2.
      故答案为ab≠1或a≠-2.
    MBTS ©2010-2016 edu.why8.cn