数列1/3,1/9,1/27,...1/3n,..各项的和S=( )
问题描述:
数列1/3,1/9,1/27,...1/3n,..各项的和S=( )
答
S=a(1)/(1-q)=(1/3)/[1-(1/3)]=1/2
数列1/3,1/9,1/27,...1/3n,..各项的和S=( )
S=a(1)/(1-q)=(1/3)/[1-(1/3)]=1/2