Các câu hỏi tương tự
Tính :
P = \(\frac{\frac{1}{19}+\frac{2}{18}+\frac{3}{17}+....+\frac{18}{2}+\frac{19}{1}}{\frac{1}{2}+\frac{1}{3}+...+\frac{1}{19}+\frac{1}{20}}\)
Tính nhanh A = \(1+\frac{1}{1+2}+\frac{1}{1+2+3}+...+\frac{1}{1+2+3+...+19}\)
So sánh \(A\)với\(13\),biết rằng:
\(A=\frac{13}{15}+\frac{7}{5}+\frac{3}{4}+\frac{1}{5}+\frac{1}{7}+\frac{19}{20}+\frac{5}{4}+\frac{1}{3}+\frac{1}{6}+\frac{1}{13}+\frac{17}{23}+\frac{9}{8}+\frac{2}{5}+\frac{1}{7}+\frac{1}{25}+\frac{3}{2}+\frac{1}{8}+\frac{1}{19}+\frac{1}{9}+\frac{1}{97}\)
Bài 1 : Tính tổng S , biết : \(S=\frac{1}{1\times2}+\frac{1}{2\times3}+\frac{1}{3\times4}+....+\frac{1}{2010\times2011}\)
Bài 2 : Tính tổng sau : \(S=\frac{3}{10\times13}+\frac{3}{13\times16}+\frac{3}{16\times19}+....+\frac{3}{58\times61}\)
Bài 3 : Tính tổng sau : \(S=\frac{1}{4\times7}+\frac{1}{7\times10}+\frac{1}{10\times13}+....+\frac{1}{19\times22}\)
\(B=1+\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+...+\frac{1}{1+2+...+19}\)
Tính: \(1+\frac{1}{1+2}+\frac{1}{1+2+3}+...+\frac{1}{1+2+3+...+19}=?\)
Giải giúp mình bài này với.
\(1+\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+...+\frac{1}{1+2+3+4+...+19}\)
tinh tong A+\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3+4}+...\frac{1}{18\cdot19}+\frac{1}{19\cdot20}\)
tính nhanh
A= \(\frac{3}{1}+\frac{3}{1+2}+\frac{3}{1+2+3}+\frac{3}{1+2+3+4}+......+\frac{3}{1+2+3+4+.....+100}\)