Question

b1=2 b2=4 b3=8 найти b6? И Sn?

Answer 1

$b_1=2; b_2=4; b_3=8\b_6=b_1*q^5\q=b_2:b_1=4^2=2\b_6=2*2^5=2^6=64\\S_6= frac{b_1(1-q^6)}{1-q}= frac{2*(1-64)}{1-2}= frac{2*(-63)}{-1}=126$