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標題:

數學.............

發問:

1 )simplify log (a^2 ) +log (b^4) /log (ab^2 ) ,where a,b >0 ANs 2 2 ) m^-1 - n^-1 /m ^-2 - n ^-2 Ans mn/m+n

最佳解答:

1 log (a^2 ) +log (b^4) /log (ab^2 ) =(2loga + 4logb)/(loga +2logb) =2(loga + 2logb)/(loga + 2logb) =2 2 m^-1 - n^-1 /m ^-2 - n ^-2 =(1/m - 1/n) / (1/m^2 - 1/n^2) =[(n-m)/mn] / [(n^2-m^2)/(m^2 n^2)] =[(n-m)/mn] / [(n-m)(n+m)/(mn^2)] =1 / [(m+n)/mn] =mn/m+n

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其他解答:

1) log (a^2 ) +log (b^4) /log (ab^2 ) =[2log(a)+4log(b)]/[log(a)+2log(b)] =2[log(a)+2log(b)]/[log(a)+2log(b)] =2 2008-01-10 17:34:44 補充: m^-1 - n^-1 /m ^-2 - n ^-2=[1/m-1/n]/[1/m^2-1/n^2]=[(n-m)/mn]/[(n^2-m^2)/(mn)^2]=(n-m)/[(n-m)(n+m)]/nm]=nm/(n+m)
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