计算:1/1x2+1/2x3+1/3X4+...+1/9x10=?
问题描述:
计算:1/1x2+1/2x3+1/3X4+...+1/9x10=?
答
1/1x2+1/2x3+1/3X4+...+1/9x10
=1-1/2+1/2-1/3+1/3-1/4+……+1/9-1/10
=1-1/10
=9/10