\(2B=2\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{23}-\frac{1}{25}\right)\)
\(2B=2\left(\frac{1}{3}-\frac{1}{25}\right)\)
\(2B=2\times\frac{22}{75}\)
\(B=\frac{44}{75}\)
Tính: A = 4/5.7 + 4/7.9 + 4/9.11 + ... + 4/21.23 + 4/23.25
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 nhanh tổng sau:
A=1/3+1/6+1/10+1/15+1/21+1/28
B=1/5.7+1/7.9+1/9.11+....+1/23.25
tính B=1/3.5+1/5.7+1/7.9+...+1/37.39
1/3.5 + 1/5.7 + 1/7.9 + ... + 1/97.99
1/3.5+1/5.7+1/7.9+...+1/99.101=?
B=1/3.5+1/5.7+1/7.9+1/9.11+1/11.13
Tinh B
tính A=1/3.5+1/5.7 +1/7.9 + ... +1/37.39
