2/1*3+2/3*5+2/5*7+.+2/97*99=2/99*101

问题描述:

2/1*3+2/3*5+2/5*7+.+2/97*99=2/99*101
*=× /=分之

2/1*3+2/3*5+2/5*7+.+2/97*99+2/99*101
=1-1/3+1/3-1/5+1/5-1/7+...+1/97-1/99+1/99-1/101
=1-1/101
=100/1011-1/3+1/3-1/5+1/5-1/7+...+1/97-1/99+1/99-1/101怎么来的?2/1*3=1-1/3