2/1x3+2/3X5+2/5x7=2/7x9+2/9x11计算..

问题描述:

2/1x3+2/3X5+2/5x7=2/7x9+2/9x11
计算..

=(1-1/3)+(1/3-1/5)+...+(1/9-1/11)=10/11
中间的=号应该是+

2/1x3+2/3X5+2/5x7+2/7x9+2/9x11=1-1/3+1/3-1/5.+1/9-1/11=1-1/11=10/11