Question

[Yến Nhi]

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1/1×2 + 1/2×3 +  1/3×4 + 1/4×5 +.....+1/2017×2017

Answer 1

[o0o Hinata o0o]

\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+....+\frac{1}{2017.2018}\)

\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2017}-\frac{1}{2018}\)

\(=\frac{1}{1}-\frac{1}{2018}\)

\(=\frac{2017}{2018}\)

Answer 2

[Linh Kẹo]

= 1/1- 1/2+...+1/2017-1/2018

=1-1/2018

=2017/2018

k mk nha các bạn