\(\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+...+\frac{1}{49.51}\)
=\(\frac{1}{2}\left(\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+...+\frac{2}{49.51}\right)\)
=\(\frac{1}{2}\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{49}-\frac{1}{51}\right)\)
=\(\frac{1}{2}\left(\frac{1}{3}-\frac{1}{51}\right)\)
=\(\frac{1}{2}.\frac{16}{51}\)
=\(\frac{8}{51}\)
\(\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+..........+\frac{1}{49.51}=?\)
3/3.5+3/5.7+3/7.9+...+3/49.51 = ?
các bạn cho mk hỏi câu này
2/3.5+2/5.7+2/7.9+...+2/97.99
thì mk sẽ viết thành
1/3.5+1/5.7+1/7.9+...+1/97.99
hay
2.(1/3.5+1/5.7+1/7.9+...+1/97.99)
giúp mk với
Tính B=\(\frac{1.3}{3.5}+\frac{2.4}{5.7}+\frac{3.5}{7.9}+.....+\frac{49.51}{99.101}\)
B= 1/3.5 + 1/5.7+...+1/49.51
Tính nahnh
1/3.5 + 1/5.7 +...... + 1/49.51
\(A=\frac{3}{3.5}+\frac{3}{5.7}+\frac{3}{7.9}+...+\frac{3}{49.51}=?\)
1/3.5 + 1/5.7 + 1/7.9 + ... + 1/97.99
1/3.5+1/5.7+1/7.9+...+1/99.101=?
