(Log2)的三次方+(Log5)的三次方+3*lg2*lg5=?
问题描述:
(Log2)的三次方+(Log5)的三次方+3*lg2*lg5=?
答
(log2)^3+(log5)^3+3lg2lg5=(log2+log5)((log2)^2-log2log5+(log5)^2)+3log2log5=log(2*5)((log2)^2+2log2log5+(log5)^2-3log2log5)+3log2log5=log10((log2+log5)^2-3log2log5)+3log2log5=1*((log10)^2-3log2log5)+3...