是不是這樣的:loga(x^2+4)+loga(y^2+1)=loga5+loga(2xy-1)(a>0,a≠1)
依題意可得:(x²+4)(y²+1) = 5(2xy-1) ,
整理得:(xy-3)²+(x-2y)² = 0 ;
因為,(xy-3)² ≥ 0 ,(x-2y)² ≥ 0 ,
所以,xy-3 = 0 ,x-2y = 0 ;
可得:x = 2y ,
即有:y/x = 1/2 ,
所以,log根號2(y/x) =2 log2(1/2) = -2 .問下下哈:依題意可得:(x2+4)(y2+1) = 5(2xy-1) ,之后是怎么整理到下一步的???:(x²+4)(y²+1) = 5(2xy-1) ,x^2y^2+x^2+4y^2+4=10xy-5(x^2y^2-6xy+9)+(x^2-4xy+4y^2)=0(xy-3)^2+(x-2y)^2=0x-2y=0即有:x/y = 2 ,所以,log根號2(x/y) =2 log2(2) =2 。
已知log a (x^2+4)+log a (y^2+1)=log a (2xy-1)(a>0,且a≠1),求log 根號下2 x/y的值
已知log a (x^2+4)+log a (y^2+1)=log a (2xy-1)(a>0,且a≠1),求log 根號下2 x/y的值
有些數(shù)學(xué)符號沒辦法打,見諒~
有些數(shù)學(xué)符號沒辦法打,見諒~
數(shù)學(xué)人氣:561 ℃時間:2020-02-01 00:43:20
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