Question

2/1x3+2/3x5+....+2/199x201 =?

Answer 1

\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+.....+\frac{2}{199.201}\)

= \(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+.....+\frac{1}{199}-\frac{1}{201}\)

= \(1-\frac{1}{201}\)

= \(\frac{200}{201}\)

Answer 2

2/1x 3 + 2/3x5+..+2/199x201

= 1/1 - 1/3 + 1/3 - 1/5 + ... + 1/199 - 1/201

= 1/1 - 1/201

= 200/201 

( đúng cho m,ình nha)_