\(C=\frac{1}{1.4}+\frac{1}{4.7}+...+\frac{1}{52.55}+\frac{1}{55.58}\)
\(\Rightarrow C=\frac{1}{3}.\left(\frac{3}{1.4}+\frac{3}{4.7}+...+\frac{3}{52.55}+\frac{3}{55.58}\right)\)
\(\Rightarrow C=\frac{1}{3}.\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{52}-\frac{1}{55}+\frac{1}{55}-\frac{1}{58}\right)\)
\(\Rightarrow C=\frac{1}{3}.\left(1-\frac{1}{58}\right)\)
\(\Rightarrow C=\frac{1}{3}.\frac{57}{58}\)
\(\Rightarrow C=\frac{19}{58}\)
Vậy \(C=\frac{19}{58}\)
~ Ủng hộ nhé
\(3C=\frac{3}{1\times4}+\frac{3}{4\times7}+...+\frac{1}{55\times58}..\)
\(3C=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}....+\frac{1}{55}-\frac{1}{58}..\)
\(3C=1-\frac{1}{58}=\frac{57}{58}\)
\(C=\frac{57}{174}\)
Ai tên triết đừng xem nhé ahihi
\(3C=\frac{3}{1.4}+\frac{3}{4.7}+...+\frac{3}{55.58}\)
\(3C=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+....+\frac{1}{55}-\frac{1}{58}\)
\(3C=1-\frac{1}{58}=\frac{57}{58}\)
\(C=\frac{57}{\frac{58}{3}}=\frac{19}{58}\)
