\(A=\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+..+\frac{1}{1098.1100}\)
\(A=\frac{1}{2}-\frac{1}{4}+..+\frac{1}{1098}-\frac{1}{1100}\)
\(A=\frac{1}{2}-\frac{1}{1100}\)
\(A=\frac{549}{1100}\)
A = \(\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+...+\frac{1}{1098.1100}\)
= \(\frac{1}{2}\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{1098}-\frac{1}{1100}\right)\)
= \(\frac{1}{2}\left(\frac{1}{2}-\frac{1}{1100}\right)\)
= \(\frac{1}{2}.\frac{549}{1100}\)
= \(\frac{549}{2200}\)
Mấy bạn làm sai rùi. Bài này phải làm là 2A chứ