log25(底数)9(真数)×log27(底数)625(真数)=?
问题描述:
log25(底数)9(真数)×log27(底数)625(真数)=?
答
log25(9)*log27(625)
=log(5^2)(3^2)*log(3^3)(5^4)
=[lg(3^2)/lg(5^2)]*[lg(5^4)/lg(3^3)]
=[2lg3*4lg5]/[2lg5*3lg3]
=4/3