已知log2(6)=a 求log2(18)

问题描述:

已知log2(6)=a 求log2(18)

∵log2(6)=log2(2*3)=log2(2)+log2(3)=1+log2(3)=a
∴log2(3)=a-1
∴log2(18)=log2(3*6)=log2(3)+log2(6)=a-1+a=2a-1