log18^3=a,18^b=5,log18^45=
问题描述：
log18^3=a,18^b=5,log18^45=
已知log18^3=a,18^b=5,则log18^45=
答
由题意可得 a=log18(3)b=log18(5)log36(45)=log18(45)/log18(36)=log18(3X3X5)/log18(18X2)=[2log18(3)+log18(5)]/[1+log18(2)]=(2a+b)/[1+log18(18/9)]=(2a+b)/[1+1-log18(9)]=(2a+b)/(2-2log18(3))=(2a+b)/(2-2a) 谢谢 望采纳