Tính:
F=(\(\frac{3}{1.8}+\frac{3}{8.15}+\frac{3}{15.22}+....+\frac{3}{106.113}\) ) - (\(\frac{25}{50.55}+\frac{25}{55.60}+\frac{25}{60.65}+.....+\frac{25}{95.100}\))
\(\left(\frac{3}{1.8}+\frac{3}{8.15}+\frac{3}{15.22}+...+\frac{3}{106.113}\right)-\left(\frac{25}{50.55}+\frac{25}{55.60}+...+\frac{25}{95.100}\right)\)
Giải giúp mk với!
\(A=\frac{3}{1.8}+\frac{3}{8.15}+\frac{3}{15.22}+...+\frac{3}{106.113}\)
\(=\frac{3}{7}\left(\frac{7}{1.8}+\frac{7}{8.15}+\frac{7}{15.22}+...+\frac{7}{106.113}\right)\)
\(=\frac{3}{7}\left(\frac{8-1}{1.8}+\frac{15-8}{8.15}+\frac{22-15}{15.22}+...+\frac{113-106}{106.113}\right)\)
\(=\frac{3}{7}\left(1-\frac{1}{8}+\frac{1}{8}-\frac{1}{15}+\frac{1}{15}-\frac{1}{22}+\frac{1}{106}-\frac{1}{113}\right)\)
\(=\frac{3}{7}\left(1-\frac{1}{113}\right)=\frac{48}{113}\)
\(B=\frac{25}{50.55}+\frac{25}{55.60}+...+\frac{25}{95.100}\)
\(=5\left(\frac{5}{50.55}+\frac{5}{55.60}+...+\frac{5}{95.100}\right)\)
\(=5\left(\frac{55-50}{50.55}+\frac{60-55}{55.60}+...+\frac{100-95}{95.100}\right)\)
\(=5\left(\frac{1}{50}-\frac{1}{55}+\frac{1}{55}-\frac{1}{60}+...+\frac{1}{95}-\frac{1}{100}\right)\)
\(=5\left(\frac{1}{50}-\frac{1}{100}\right)=\frac{1}{20}\)
Giá trị của biểu thức đã cho là:
\(A-B=\frac{48}{113}-\frac{1}{20}=\frac{847}{2260}\)
1.
a) \(\text{(3x-5)6=(3x-5)4}\)
2.
a)\(\frac{2}{7}.\frac{2012}{2011}-\frac{2}{2011}.\frac{1}{7}_{ }+\frac{4}{7}\)
b) \(\left(\frac{3}{1.8}+\frac{3}{8.15}+\frac{3}{15.22}+...+\frac{3}{106.113}\right)-\left(\frac{25}{50,55}\frac{25}{55.60}\frac{25}{60.65}...\frac{25}{95.100}\right)\)
ai nhanh đúng mk tk
\(\left(\frac{1}{8}+\frac{1}{8.15}+\frac{1}{15.22}+...+\frac{1}{43.50}\right).\frac{4-3-5-...-49}{217}\)
Tìm x \(1-\left(x\%+x:50+\frac{\frac{3}{2}-\frac{3}{7}-\frac{3}{13}}{\frac{25}{2}-\frac{25}{7}-\frac{25}{13}}\times x\right)=0\)
Bài 1: Tính tổng: \(S=\frac{3}{2\cdot3}+\frac{3}{3\cdot6}+\frac{3}{4\cdot9}+...+\frac{3}{6039\cdot2014}\)
Bài 2: Rút gọn phân số: \(S=\frac{25^{28}+25^{24}+...+25^4+1}{25^{30}+25^{28}+...+25^2+1}\)
A=\(\frac{9}{8}-\frac{8}{9}+\frac{3}{25}+\frac{1}{4}-\frac{5}{16}+\frac{19}{25}-\frac{1}{9}+\frac{2}{25}-\frac{1}{81}\)
GIẢI GIÚP MÌNK NHÉ!
\(A=\frac{9}{8}-\frac{8}{9}+\frac{3}{25}+\frac{1}{4}-\frac{5}{16}+\frac{19}{25}-\frac{1}{9}+\frac{2}{25}-\frac{1}{81}\)
\(A=\left(\frac{9}{8}+\frac{1}{4}-\frac{5}{16}\right)-\left(\frac{8}{9}+\frac{1}{9}-\frac{1}{81}\right)+\left(\frac{3}{25}+\frac{19}{25}+\frac{2}{25}\right)\)
\(A=\frac{17}{16}-\frac{80}{81}+\frac{24}{25}\)
\(A=\frac{33529}{32400}\)
Thức hiện phép tính:
\(\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{\frac{4}{9}-\frac{4}{7}-\frac{4}{11}}+\frac{\frac{3}{5}-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac{4}{5}-\frac{4}{626}-\frac{4}{125}-\frac{4}{25}}\)
Tính nhanh : \(\frac{\frac{2}{33}+\frac{2}{25}+\frac{2}{19}}{\frac{3}{33}+\frac{3}{25}+\frac{3}{19}}\)
\(\frac{\frac{2}{33}+\frac{2}{25}+\frac{2}{19}}{\frac{3}{33}+\frac{3}{25}+\frac{3}{19}}=\frac{2\left(\frac{1}{33}+\frac{1}{25}+\frac{1}{19}\right)}{3\left(\frac{1}{33}+\frac{1}{25}+\frac{1}{19}\right)}=\frac{2}{3}\)
= \(\frac{2\left(\frac{1}{33}+\frac{1}{25}+\frac{1}{19}\right)}{3\left(\frac{1}{33}+\frac{1}{25}+\frac{1}{19}\right)}=\frac{2}{3}\)
\(\frac{\frac{2}{33}+\frac{2}{25}+\frac{2}{19}}{\frac{3}{33}+\frac{3}{25}+\frac{3}{19}}=\frac{2\cdot\left(\frac{1}{33}+\frac{1}{25}+\frac{1}{19}\right)}{3\cdot\left(\frac{1}{33}+\frac{1}{25}+\frac{1}{19}\right)}=\frac{2}{3}\)
Chứng minh rằng:
\(\sqrt[3]{\sqrt[5]{\frac{32}{5}}-\sqrt[5]{\frac{27}{5}}}=\sqrt[5]{\frac{1}{25}}+\sqrt[5]{\frac{3}{25}}-\sqrt[5]{\frac{9}{25}}\)