Question

[Đào Ngọc Hân]

2/2×4+2/4×6+...+2/198×200=

Answer 1

[Nguyễn Thị Thương Hoài]

A = \(\dfrac{2}{2.4}\) + \(\dfrac{2}{4.6}\) + ....+ \(\dfrac{2}{198.200}\)

A = \(\dfrac{1}{2}\) - \(\dfrac{1}{4}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{6}\) + ......+ \(\dfrac{1}{198}\) - \(\dfrac{1}{200}\)

A = \(\dfrac{1}{2}\) - \(\dfrac{1}{200}\)

A = \(\dfrac{99}{200}\)