1/(1*3)+1/(3*5)+1/(5*7).+1/(49*51)=多少/是分数线,*是乘号
问题描述:
1/(1*3)+1/(3*5)+1/(5*7).+1/(49*51)=多少
/是分数线,*是乘号
答
25/51
原式=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)