\(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}\)
Tinh ho minh
\(\frac{1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+....+\frac{1}{9}+\frac{1}{10}}{\frac{1}{1\times10}+\frac{1}{2\times9}+\frac{1}{3\times8}+....+\frac{1}{9\times2}+\frac{1}{10\times1}}\)
Tinh nhanh minh tich cho
A=\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{256}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}\)
Tinh A
Giup minh vs
toán bồi à mình làm 1 câu như vậy rùi
tinh
\(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+\frac{1}{1+2+3+4+5}\)
= \(\frac{1}{3}\)+ \(\frac{1}{6}\)+ \(\frac{1}{10}\)+ \(\frac{1}{15}\)
= \(\frac{10}{30}\)+ \(\frac{5}{30}\)+ \(\frac{3}{30}\)+ \(\frac{2}{30}\)= \(\frac{20}{30}\)= \(\frac{2}{3}\).(lấy mẫu chung là 30)
Học tốt !
\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{264}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)
tinh nhanh neu co the
\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}\cdot\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{264}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)
\(=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{2\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}\cdot\frac{\frac{3}{4}\left(1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}\right)}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}\)\(+\frac{5}{8}\)
\(\frac{1}{2}\cdot\frac{3}{4}+\frac{5}{8}=\frac{3}{8}+\frac{5}{8}=1\)
tinh nhanh
A=\(\frac{3}{1}+\frac{3}{1+2}+\frac{3}{1+2+3}+\frac{3}{1+2+3+4}+....+\frac{3}{1+2+3+.....+100}\)
\(A=\frac{3}{1}+\frac{3}{\frac{\left(2+1\right).2}{2}}+\frac{3}{\frac{\left(3+1\right).3}{2}}+....+\frac{3}{\frac{\left(100+1\right).100}{2}}\)
\(\Rightarrow A=\frac{3}{1}+\frac{6}{2.3}+\frac{6}{3.4}+...+\frac{6}{100.101}\)
\(\Rightarrow A=\frac{3}{1}+6.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-...-\frac{1}{101}\right)\)
\(\Rightarrow A=\frac{3}{1}+6.\left(\frac{1}{2}-\frac{1}{101}\right)\)
\(\Rightarrow A=\frac{3}{1}+\frac{6.99}{202}=\frac{297}{101}+\frac{3}{1}=\frac{600}{101}\)
kết quả k bik có sai k
tinh gia tri bieu thuc
A = \(3+\frac{1}{1+\frac{1}{1+\frac{1}{1+\frac{1}{3}}}}\)
\(B=-5+\frac{1}{1-\frac{1}{2+\frac{1}{1-\frac{1}{4}}}}\)
Ai làm nhanh nhat minh tk cho
\(A=3+\frac{1}{1+\frac{1}{1+\frac{1}{\frac{4}{3}}}}=3+\frac{1}{1+\frac{1}{1+\frac{3}{4}}}\)
\(=3+\frac{1}{1+\frac{1}{\frac{7}{4}}}=3+\frac{1}{1+\frac{4}{7}}=3+\frac{1}{\frac{11}{4}}=3+\frac{4}{11}=\frac{37}{11}\)
\(B=-5+\frac{1}{1-\frac{1}{2+\frac{1}{\frac{3}{4}}}}=-5+\frac{1}{1-\frac{1}{2+\frac{4}{3}}}\)
\(=-5+\frac{1}{1-\frac{1}{\frac{10}{3}}}=-5+\frac{1}{1-\frac{3}{10}}=-5+\frac{1}{\frac{7}{10}}=-5+\frac{10}{7}=\frac{-25}{7}\)
tinh B=\(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+...+\frac{1}{2016}}{\frac{2016}{1}+\frac{2003}{2}+\frac{2002}{3}+...+\frac{1}{2016}}\)
Tinh\(\frac{\frac{2010}{1}+\frac{2009}{2}+\frac{2008}{3}+...+\frac{2}{2009}+\frac{1}{2010}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+...+\frac{1}{2010}+\frac{1}{2011}}\)
Ghi lộn đề thiếu thì phải. Hình như thiếu phân số 1/2011
\(A=\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{200}\);\(B=\frac{1}{199}+\frac{2}{198}+\frac{3}{197}+...+\frac{198}{2}+\frac{199}{1}\)Tinh \(\frac{A}{B}\)Giup minh voi
A=1/1.2+1/2.3+1/3.4+... tu do tu lam nhe
- Đây http://olm.vn/hoi-dap/question/89634.html