Log(2)1/25•log(3)1/8•log(5)1/9化简 还有已知log(18)9=a,

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  • Log(2)1/25•log(3)1/8•log(5)1/9=(lg1/25/lg2)(lg1/8/lg3)(lg1/9/lg5)

    =(lg1/25/lg5)(lg1/8/lg2)(lg1/9/lg3)=(-2)(-3)(-2)=-12

    log(18)9=a,log(9)18=1/a=log(9)9+log(9)2=1+log(9)2,log(9)2=1/a-1=(1-a)/a

    log(18)9/log(18)5=log(5)9=a/b

    ,log(18)5=b,log(5)18=1/b=log(5)9+log(5)2=a/b+log(5)2,log(5)2=1/b-a/b=(1-a)/b

    log(18)9+log(18)5=log(18)45=a+b

    log(45)2=lg2/(lg5+lg9)=1/[log(2)5+log(2)9]=1/[b/(1-a)+a/(1-a)]=(1-a)/(a+b)

    log(36)45=lg45/lg18+lg2=1/[log(45)18+log(45)2]=1/[1/(a+b)+(1-a)/(a+b)]=(a+b)/(2-a)