初中数学题,最后一题怎么做求过程!

2025-03-21 19:58:39
推荐回答(3个)
回答(1):

原式=(1/2)(1-1/3+1/3-1/5+1/5-1/7+...+1/49-1/51)
=(1/2)(1-1/51)
=(1/2)*50/51
=25/51

回答(2):

=1/2 [2/(1x3)+2/(3x5)+……+2/(49x51)]
=1/2 (1- 1/3 +1/3 - 1/5+……+ 1/49 - 1/51)
=1/2(1- 1/51)
=1/2 x 50/51
=25/51

回答(3):

(2)=(1/2)(1-1/3)+(1/2)(1/3-1/5)+…………………………+(1/2)(1/49-1/51)
=(1/2)(1-1/3+1/3-1/5+………………+1/49-1/51)
=(1/2)(1-1/51)
=(1/2)(50/51)
=25/51