Odpowiedź:
a1=512
q=a2/a1=256/512=1/2
[tex]s \frac{}{n} = a \frac{}{1} \times \frac{1 - {q}^{n} }{1 - q} [/tex]
[tex]s \frac{}{12} = a \frac{}{1} \times \frac{1 - {q}^{12} }{1 - q} = 512 \times \frac{1 - ( \frac{1}{2} {)}^{12} }{ 1 - \frac{1}{2} } = 512 \times \frac{1 - \frac{1}{4096} }{ \frac{1}{2} } = 512 \times \frac{ \frac{4095}{4096} }{ \frac{1}{2} } = 512 \times \frac{4095}{4096} \times 2 = \frac{4095}{4} = 1023 \frac{3}{4} [/tex]
