Question

[Nohara shin nosuke]

1/2+1/4+1/6+1/8...+1/98+1/100

Tổng là?

Answer 1

[Đàm Thị Minh Hương]

Đặt A  =1/2 + 1/4 + 1/6 + 1/8 + .... + 1/98 + 1/100

   2A = 2. (1/2 + 1/4 + 1/6 + 1/8 + .... + 1/98 + 1/100)

   2A = 1 + 1/2 + 1/3 + 1/4 + ... + 1/49 + 1/50

=> 2A - A = (1 + 1/2 + 1/3 + 1/4 +.... +1/49 + 1/50 ) - ( 1/2 +1/4 + 1/6 +1/8 + ...+1/98 + 1/100)

<=> A = 1 + 1/3 + 1/5 +... + 1/49 - 1/52 - 1/54 - 1/56 - ... - 1/98 - 1/100

Answer 2

[Nohara shin nosuke]

98/100