Question

1/1*3+1/3*5+1/5*7+1/7*9+......+1/49*51

Answer 1

1/1*3 = （1-1/3）*(1/2)
1/3*5 = （1/3-1/5）*(1/2)
....

1/(1*3)+1/(3*5)+1/(5*7)+1/(7*9)+......+1/(49*51)
= (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)
= 25/51

追问

谢谢O(^-^)O

Answer 2

1/1*3=1/2(1-1/3) 1/3*5=1/2(1/3-1/5)
1/7*9=1/2(1/5-1/7)
1/1*3+1/3*5+1/5*7+1/7*9+......+1/49*51
=1/2(1-1/3+1/3-1/5+........-1/51)
=1/2(1-1/51)
=25/51
希望能帮助你

追问

谢谢!0^-^0……

追答

以后有这类问题 可以直接找我

追问

o(^-^)o嗯,谢谢!

追答

吧我的设成满意吧

Answer 3

1/1*3+1/3*5+1/5*7+1/7*9+......+1/49*51
=1/2*[1/1-1/3]+1/2*[1/3-1/5]+……+1/2*[1/49-1/51]
=1/2*[1-1/51]=25/51

追问

谢谢!0^-^0……