1/1*3*5+1/3*5*7+1/5*7*9.+1/95*97*99

题目

1/1*3*5+1/3*5*7+1/5*7*9.+1/95*97*99

答案

"1/1*3*5=1/4(1/1*3-1/3*5)1/3*5*7=1/4(1/3*5-1/5*7).如上拆开后两两抵消最后剩下1/4(1/1*3-1/97*99)