Відповіді §.19 - §.20 » §.20 (2.3)

Sn = 105, xn = 56, q = 2. Sn = (x_1 (q^n- 1))/(q-1) xn = x1 • qn–1; x1 • 2n–1 = 56 x1 = 56/2^(n-1) Sn = (x_1 (q^n- 1))/(q-1) (56 •(2^n- 1))/(2^(n-1) (2-1)) = 105. (2^n- 1)/2^n = 15/16 1/2^n = 1 – 15/16 1/2^n = 1/16 2n = 16. n = 4.