\(C=1+\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{100}}\)
\(2C=2+1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{99}}\)
\(2C-C=\left(2+1+\frac{1}{2}+\frac{1}{2^2}+...+2^{99}\right)-\left(1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{100}}\right)\)
\(\Rightarrow C=2-\frac{1}{2^{100}}\)
Ủng hộ mk nha bn !!! ^_^
2C= 2+1+1/2+1/22+.....+1/299
2C-C= ( 2+1+1/2+1/22+.....+1/299 ) - (1+1/2+1/22+1/23+.....+1/2100)
C= 2 - 1/2100
C=2
C=1+1/2+1/22+1/23+...+1/2100
=>C/2=1/2+1/22+1/23+1/24+...+1/2101
=>C-C/a=(1+1/2+1/22+1/23+...+1/2100)-(1/2+1/22+1/23+1/24+...+1/2101)
C/2=1-1/2101
=>C=2*2101-1/2101
=2101-1/2100
Vậy C=2101/2100