计算: 2log5,25-3log2,64 1og2(log2,16) 换底公式是什么? 换底公式不...答:2log5,25-3log2,64= 2×2-3×6=-14 1og2(log2,16) =log2,4=2 换底公式就是 log(a)(b)=log(s)(b)/log(s)(a)推导过程:设log(s)b=M,log(s)a =N,log(a)b=R 则s^M=b,s^N=a,a^R=b 即(s^N)^R=a^R=b s^(NR)=b 所以M=NR,即R=M/N,log(a)b...