\(\frac{1}{3}-\frac{1}{18}-\frac{1}{54}-\frac{1}{108}-\frac{1}{180}-\frac{1}{270}-\frac{1}{378}\)
Tính: \(A=\frac{1}{3}-\frac{1}{8}-\frac{1}{54}-\frac{1}{108}-\frac{1}{180}-\frac{1}{270}-\frac{1}{378}\)
Các cậu giuos mình nha! Cả 2 câu mk vừa đăng nữa
cho \(A=\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{107}+\frac{1}{108}\);\(B=\frac{108}{1}+\frac{107}{2}+\frac{106}{3}+...+\frac{2}{107}+\frac{1}{108}\).tính\(\frac{A}{B}\)
Tính :
a)\(\left[-\frac{1}{2}\right]^2:\frac{1}{4}-2\left[-\frac{1}{2}\right]^2\)
b)\(-\frac{7}{37}.1\frac{3}{8}-4\frac{5}{8}.\frac{7}{12}+\frac{1}{2}\)
c)\(F=\frac{1}{18}+\frac{1}{54}+\frac{1}{108}+...+\frac{1}{990}\)
d)\(H=\frac{4}{2.4}+\frac{4}{4.6}+\frac{4}{6.8}+...+\frac{4}{2018.2020}\)
Tính A=\(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{18}+\frac{1}{19}+\frac{1}{20}}{\frac{19}{1}+\frac{18}{2}+\frac{17}{3}+...+\frac{3}{17}+\frac{2}{18}+\frac{1}{19}}\)
Tính tổng:
\(S=\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+...+\frac{1}{1+2+3+4+...+2016+2017}\)
A=\(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+....+\frac{1}{108}+\frac{1}{109}\)và B=\(\frac{108}{1}+\frac{107}{2}+\frac{106}{3}+....+\frac{2}{107}+\frac{1}{108}\)
Tính nhanh
A=\(\frac{1}{10}-\frac{1}{40}-\frac{1}{88}-\frac{1}{154}-\frac{1}{238}-\frac{1}{340}\)
B=\(\frac{1}{3}-\frac{1}{8}-\frac{1}{54}-\frac{1}{108}-\frac{1}{180}-\frac{1}{270}-\frac{1}{378}\)
Ai nhanh và đúng mình tick cho
Tính tổng :\(S=1+\frac{1}{2}.\left(1+2\right)+\frac{1}{3}.\left(1+2+3\right)+\frac{1}{4}.\left(1+2+3+4\right)+....+\frac{1}{50}.\left(1+2+3+4+....+50\right)\)