\(\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+...+\frac{2}{99.100}\)
= \(2.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\right)\)
= \(2.\left(1-\frac{1}{100}\right)\)
= \(2.\frac{99}{100}\)
= \(\frac{99}{50}\)
\(\frac{x}{200}=\frac{1^2}{1.2}.\frac{2^2}{2.3}...\frac{99^2}{99.100}\) tìm x nha
\(\frac{x}{101}=\frac{2^2}{1.3}.\frac{3^2}{2.4}...\frac{100^2}{99.101}\)
tinh: 1/1.2+1/2.3+1/2.4+....+1/99.100
Tính:
a) \(\frac{1^2}{1.2}.\frac{2^2}{2.3}.\frac{3^2}{3.4}...\frac{99^2}{99.100}.\frac{100^2}{100.101}\)
b)\(\frac{2^2}{1.3}.\frac{3^2}{2.4}.\frac{4^2}{3.5}...\frac{59^2}{58.60}\)
C=3^50-3^49+3^48-3^47=...=3^2-3+!
E=1.2+2.3+3.4+...+99.100
H=1.3+2.4+3.5+...+97.99+98.100
Tính tổng: M=1.2+2.3+....+48.49 N=1+2+...+48 A=1.2+2.3+...+99.100 Cảm ơn
A=\(\frac{1}{1.2^2}\)+\(\frac{1}{2.3^2}\)+\(\frac{1}{2.4^2}\)+...+\(\frac{1}{99.100^2}\)
Chứng minh A<\(\frac{4}{9}\)
S=2/1.2+2/2.3+2/3.4+............+2/98.99+2/99.100
tính tổng : A=1.5 + 5.9 + ....+97.101+101.105
B=1.2^2+2.3^2+3.4^2+....+99.100^2
C=1.2+3.4+5.6+7.8+...+99.100
D=1.2.3+2.3.4+...+98.99.100
P = \(\dfrac{2}{1.2}+\dfrac{2}{2.3}+\dfrac{2}{3.4}+...+\dfrac{2}{99.100}\)
