Có \(E=\frac{1}{1.101}+...+\frac{1}{10.110}=\frac{1}{100}\left(\frac{1}{1}-\frac{1}{101}+\frac{1}{2}-\frac{1}{102}+...+\frac{1}{10}-\frac{1}{110}\right)\)
\(E=\frac{1}{100}\left(\left(\frac{1}{1}+\frac{1}{2}+...+\frac{1}{10}\right)-\left(\frac{1}{101}+\frac{1}{102}+...+\frac{1}{110}\right)\right)\)
Có \(F=\frac{1}{1.11}+...+\frac{1}{100.110}=\frac{1}{10}\left(\frac{1}{1}-\frac{1}{11}+\frac{1}{2}-\frac{1}{12}+...+\frac{1}{100}-\frac{1}{110}\right)\)
\(F=\frac{1}{10}\left(\left(\frac{1}{1}+...+\frac{1}{100}\right)-\left(\frac{1}{10}+...+\frac{1}{110}\right)\right)=\frac{1}{10}\left(\left(\frac{1}{1}+...+\frac{1}{10}\right)-\left(\frac{1}{101}+...+\frac{1}{110}\right)\right)\)Từ 2 kết quả trên ,suy ra E/F=1/10 hay F/E=10
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có ai kb ko teo FA VÃI LUÔN