Question

[van hai]

Tính

A= \(\dfrac{3^2}{8.11}\)+ \(\dfrac{3^2}{18.21}\)+ \(\dfrac{3^2}{14.17}\)+......+ \(\dfrac{3^2}{197.200}\)

B= \(\dfrac{1}{25.27}\)+ \(\dfrac{1}{27.29}\)+ \(\dfrac{1}{29.31}\)+....+ \(\dfrac{1}{73.75}\)

các bạn giải ra giúp mik nha ! Thanks

Answer 1

[Nguyễn Quang Ngọc Trác]

B=1/2. (2/25.27+2/27.29+2/29.31+....+2/73.75) B=1/2. (1/25-1/27+1/27-1/29+1/29-1/31+....+1/73-1/75) B=1/2. (1/25-1/75) B=1/2. 2/75 B=1/75

Answer 2

[nguyễn Thị Bích Ngọc]

\(3A=\dfrac{3}{8.11}+\dfrac{3}{18.21}+..+\dfrac{3}{197.200}\)