\(=\dfrac{1}{2}\cdot\left(\dfrac{2}{1\cdot2\cdot3}+\dfrac{2}{2\cdot3\cdot4}+...+\dfrac{2}{50\cdot51\cdot52}\right)\)
\(=\dfrac{1}{2}\left(\dfrac{1}{1\cdot2}-\dfrac{1}{2\cdot3}+\dfrac{1}{2\cdot3}-\dfrac{1}{3\cdot4}+...+\dfrac{1}{50\cdot51}-\dfrac{1}{51\cdot52}\right)\)
\(=\dfrac{1}{2}\left(\dfrac{1}{2}-\dfrac{1}{51\cdot52}\right)\)
\(=\dfrac{1}{2}\cdot\dfrac{1325}{2652}=\dfrac{1325}{5304}\)
Tính \(1\frac{1}{2}+2\frac{2}{3}+3\frac{3}{4}+4\frac{4}{5}+...+50\frac{50}{51}+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{51}\)
Cho A=1/1*2+1/3*4+...+1/99*100 và B=1/50+1/51+1/52+...+1/100 . Tính: A-B=?
\(1\frac{1}{2}+2\frac{2}{3}+3\frac{3}{4}+...+50\frac{50}{51}+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...\frac{1}{51}\)
Giúp mình giải câu này với Tính B= -1/3+1/3^2-1/3^3+1/3^4-1/3^5+...+1/3^50-1/3^51
chứng minh rằng:
1-1/2+1/3-1/4+1/5-1/6+....+1/99-1/100=1/51+1/52+....+1/100
= ?
Tính: \(1\frac{1}{2}+2\frac{2}{3}+3\frac{3}{4}+...+50\frac{50}{51}+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{51}\)= ________?
Chứng Minh:
1/1*2+1/3*4+1/5*6+...+1/97*98+1/99*100=1/51+1/52+1/53+...+1/99+1/100
,E= - 1/3 + 1/(3 ^ 2) - 1/(3 ^ 3) + 1/(3 ^ 4) -...+ 1 3^ 50 - 1 3^ 51
