Răspuns :
[tex]\it S(2^9)=\dfrac{2^{10}-1}{2-1}=1024-1=1023[/tex]
Sau:
[tex]\it S=1+2+2^2+2^3+\ ...\ +2^9\\ \\ 2S=2+2^2+2^3+\ ...\ +2^9+2^{10}\\ \\ 2S-S=2^{10}-1 \Rightarrow S=1024-1\Rightarrow S=1023[/tex]
[tex]\it S(2^9)=\dfrac{2^{10}-1}{2-1}=1024-1=1023[/tex]
Sau:
[tex]\it S=1+2+2^2+2^3+\ ...\ +2^9\\ \\ 2S=2+2^2+2^3+\ ...\ +2^9+2^{10}\\ \\ 2S-S=2^{10}-1 \Rightarrow S=1024-1\Rightarrow S=1023[/tex]