\(b=\frac{2}{2\times3}+\frac{2}{3\times5}+\frac{2}{5\times7}+...+\frac{2}{99\times101}\)
\(b=\left(\frac{1}{3}+\frac{1}{3}\right)-\left(\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{99}\right)-\frac{1}{101}\)
\(b=\frac{2}{3}-\frac{1}{101}=\frac{202}{303}-\frac{3}{303}\)
\(b=\frac{199}{303}\)
Tính tổng:
A=1/1.2+1/2.3+1/3.4+...+1/99.100
B= 1/1.3+1/3.5+1/5.7+...+1/99.101
2.4 + 4.6 + 6.8 + ...+ 98.100 + 100.102
1.3 +3.5 +5.7+ ... + 97.99 + 99.101
mọi ng giải giúp mk 2 câu này với
1.3+3.5+5.7+...+99.101
tinh a= 1.3+3.5+5.7+...+99.101
B=\(\dfrac{-1}{3}\)+ \(\dfrac{-1}{3.5}\)+ \(\dfrac{-1}{5.7}\)+ \(\dfrac{-1}{7.9}\) +... + \(\dfrac{-1}{99.101}\)
thực hiện phép tính :
\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{99.101}\)
\(\frac{2^{10}.3^{31}+2^{40}.3^6}{2^{11}.3^{31}+2^{41}.3^6}\)
tinh
1.3+3.5+5.7+.......+99.101
Tính tổng
S= 1.3+3.5+5.7+......+99.101
1) Tính 2/3.5+2/5.7+2/7.9+2/9.11+2/11.13+2/13.15+2/1.2+2/2.3+2/3.4+2/4.5+...+2/9.10
2) Tìm x biết: (11/12+11/12.24+11/23.34+...+11/89.100)
