+\infty}Q_n = 1/(1-q) \ (|q| < 1)\\\\ S = b1/(1-q)\\\\ S = 6/(1,5) = 4" alt="S = b1 + b2 + b3 + ... + b_n + ...\\\\ b_n = b_1*q^{n-1}\\\\ S = b_1 + b_1*q + b_1*q^2 + ... + b_1*q^{n-1} + ...\\\\ S = b_1(1 + q + q^2 + ... + q^{n-1} + ...)\\\\ Q_n = 1 + q + q^2 + ... + q^{n-1}\\\\ lim_{n -> +\infty}Q_n = 1/(1-q) \ (|q| < 1)\\\\ S = b1/(1-q)\\\\ S = 6/(1,5) = 4" align="absmiddle" class="latex-formula">