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log2 9×log3 2怎么算?

利用对数换底公式: log2 9×log3 2 =(lg9/lg2)×(lg2/lg3) =(2lg3/lg2)×(lg2/lg3) =2。

log2(9)=log2(3²)=2log2(3) ∴log2(9)×log3(2)=2log2(3)×log3(2) =2×1 =2 望采纳

如图

log2(log3(x))=1 log3(x)=2 x=9

解 log2(9)×log3(8) =log2(3²)×log3(2³) =2log2(3)×3log3(2) =6×log2(3)×log3(2) =6×1 =6

原式=(lg9/lg2)x(lg4/lg3)=(2lg3/lg2)x(2lg2/lg3)=4

log2 4+log3 9=2+2=4.

原式 =(lg25/lg2)*(lg4/lg3)*(lg9/lg5) =(lg25/lg5)*(lg4/lg2)*(lg9/lg3) =2*2*2 =8

m=根号6,用换底公式,对数都换成以m为底的再通分,合并,消去分母,计算即可

log2 12-log2 4=log2 (12/3)=log2 3

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