tính các tổng sau
B=\(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}\)
C=\(\frac{3}{4}+\frac{3}{28}+\frac{3}{70}+\frac{3}{130}+\frac{3}{208}\)
giải giúp mình nha
\(Tính:\)
\(A=\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{56}\)
\(B=\frac{2}{1.3}+\frac{2}{3.5}+...+\frac{2}{11.13}\)
\(C=\frac{3}{4}+\frac{3}{28}+\frac{3}{70}+\frac{3}{130}+\frac{3}{208}+\frac{3}{304}\)
\(D=\frac{1}{2}+\frac{1}{14}+\frac{1}{35}+\frac{1}{65}+\frac{1}{104}+\frac{1}{152}\)
\(S=\frac{3^2}{4}-\frac{3^2}{28}-\frac{3^2}{70}-....-\frac{3^2}{868}\)
Tính nhanh:
a) \(\frac{3^2}{1.4}+\frac{3^2}{4.7}+\frac{3^2}{7.10}+\frac{3^2}{10.13}+\frac{3^2}{13.16}+...+\frac{3^2}{97.100}\)
b)\(\frac{1}{10}+\frac{1}{40}+\frac{1}{88}+\frac{1}{154}+\frac{1}{238}+\frac{1}{940}\)
c) A= \(\frac{6}{4}+\frac{6}{28}+\frac{6}{70}+\frac{6}{130}+\frac{6}{208}\)
d) M= \((1-\frac{1000}{2016}).(1-\frac{1001}{2016}).(1-\frac{1002}{2016})...(1-\frac{2017}{2016})\)
e) A= \(8400.(\frac{1}{1.5}+\frac{1}{5.9}+\frac{1}{9.13}+\frac{1}{13.17}+\frac{1}{17.21}+\frac{1}{21.25})\)
f) T= \((\frac{1}{2}+1).(\frac{1}{3}+1).(\frac{1}{4}+1)...(\frac{1}{98}+1).(\frac{1}{99}+1)\)
h) A=\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{90}\)phần \(\frac{1}{5}+\frac{5}{3}+\frac{5}{6}+\frac{1}{2}+...+\frac{1}{9}\)
Tính tổng hợp lí:
a) \(\frac{3}{4}+\frac{3}{28}+\frac{3}{70}+\frac{3}{130}+\frac{3}{208}+\frac{3}{304}+\frac{3}{418}+\frac{3}{550}\)
b) \(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+......+\frac{2}{\left(2n+1\right).\left(2n+3\right)}\)
C) \(\frac{7+\frac{7}{13}-\frac{7}{48}+\frac{7}{95}}{15+\frac{15}{13}-\frac{15}{48}+\frac{15}{95}}-\frac{7070707}{15151515}\)
BÀI HƠI KHÓ GIẢI ĐẦY ĐỦ+ CHI TIẾT VÀ DỄ HIỂU CHO MÌNH NHA
Tính nhanh: \(\frac{6}{4}+\frac{6}{28}+\frac{6}{70}+\frac{6}{130}\)
Tìm x :
\(\left(7\frac{1}{2}\cdot8\frac{3}{70}+8\frac{3}{70}\cdot\frac{9}{4}+\frac{19}{4}\cdot8\frac{3}{70}+5\frac{1}{2}\cdot8\frac{3}{70}\right):x=1126\)
Giúp em với các anh chị , thầy cô ơi em gấp lắm
\(\left(7-\frac{4}{3}+\frac{1}{3}\right)-\left(6+\frac{5}{4}-\frac{4}{3}\right)-\left(5-\frac{7}{4}+\frac{5}{3}\right)\)=?
Tính nhanh :
\(A=\frac{12}{4}+\frac{12}{28}+\frac{12}{70}+\frac{12}{130}+...+\frac{12}{94.97}\)
