\(\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+...+\frac{2}{99.100}\)
= \(2.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\right)\)
= \(2.\left(1-\frac{1}{100}\right)=2.\frac{99}{100}\)
= \(\frac{99}{50}\)
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
S=2/1.2+2/2.3+2/3.4+............+2/98.99+2/99.100
P = \(\dfrac{2}{1.2}+\dfrac{2}{2.3}+\dfrac{2}{3.4}+...+\dfrac{2}{99.100}\)
Tính tổng S= 2/1.2 + 2/2.3 + 2/3.4 +............+ 2/98.99 + 2/99.100
\(A=1.2^2+2.3^2+3.4^2+...+99.100^2\)
\(\dfrac{x}{200}\)= \(\dfrac{1^2}{1.2}\) . \(\dfrac{2^2}{2.3}\) . \(\dfrac{3^2}{3.4}\) . .... .\(\dfrac{99^2}{99.100}\)
B=1.2^2+2.3^2+3.4^2+4.5^2+...+99.100^2
đúng mình sẽ tick cho
Tính
\(1.2^2+2.3^2+3.4^2+...+99.100^2\)
Tính A = 1.22 + 2.32 + 3.42 + …. + 99.1002
