计算:1除以[1/(2*3)+1/(3*4)+.1/(99*100)=()
问题描述:
计算:1除以[1/(2*3)+1/(3*4)+.1/(99*100)=()
快
答
1除以[1/(2*3)+1/(3*4)+.1/(99*100)
=1/[1/2-1/3+1/3-1/4+...+1/99-1/100]
=1/(1/2-1/100)
=100/49
=2又2/49