已知实数a b满足4a^2+b^2+4a-12b+37=0,求根号a^2-2ab的值

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已知实数ab满足4a^2+b^2+4a-12b+37=0,求根号a^2-2ab的值已知实数ab满足4a^2+b^2+4a-12b+37=0,求根号a^2-2ab的值已知实数ab满足4a^2+b^2+4

已知实数a b满足4a^2+b^2+4a-12b+37=0,求根号a^2-2ab的值
已知实数a b满足4a^2+b^2+4a-12b+37=0,求根号a^2-2ab的值

已知实数a b满足4a^2+b^2+4a-12b+37=0,求根号a^2-2ab的值
4a²+b²+4a-12b+37=0

  (4a²+4a+1)+(b²-12b+36)=0
亦即
  (2a+1)²+(b-6)²=0
从而
  2a+1=0
  b-6=0

  a=-1/2
  b=6
  √(a²-2ab)
  =√(1/4+6)
  =5/2
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4a^2+b^2+4a-12b+37=0
(2a+1)^2+(b-6)^2=0
利用非负数性质得
(2a+1)^2=0,(b-6)^2=0
a=-1/2,b=6
根号a^2-2ab=根号(1/4+2*1/2*6)=5/2


4a^2+b^2+4a-12b+37
=4a^2+4a+1+b^2-12b+36
=(2a+1)^2+(b-6)^2
=0
可得 2a+1=0,b-6=0
即 a=-1/2,b=6
a^2-2ab
=(-1/2)^2-2×(-1/2)×6
=1/4 + 6
=25/6
√(a^2-2ab) = 5√6/6