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log2^3=a,log5^2=b,试用a,b表示log2^45

题目详情
log2^3=a,log5^2=b,试用a,b表示log2^45
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答案和解析
b=log5^2=log2^2/log2^5=1/log2^5,故log2^5=1/b
log2^45=log2^5+log2^9=log2^5+2log2^3=1/b+2a