ПОВТОРЕННЯ НАВЧАЛЬНОГО МАТЕРІАЛУ » §.3 (3.4-5)

4. S8 = 765; q = 2; b1, b8 – ? (b_1 (q^8- 1))/(q-1) = 765. (b_1 (2^8- 1))/(2-1) = 765; b1 • (256 – 1) = 784; b1 = 3; b8 = b1q7 = 3 • 27 = 381; 5. b3 на 75% менше b1; b2 = –6; S6 – ? b2 = b1 • q –6; b1 – b3 = 0,75b1; b1q = –6; b1 – b1q2 = 0,75b1; b1q = –6; 0,25b1 – b1a2 = 0; b1q = –6; b1(0,25 – q2) = 0; S6 = (b_1 (q^6- 1))/(q-1); q2 = 0,25; q = ±0,5; b1 = ∓ 12. q = 0,5 S6 = (-12(1/64- 1))/( 0,5-1) = 24 • (–63/64) = –189/8 = 23,628; q = –0,5 S6 = (12(1/(64-1)))/(-1,5) = –8 • (–63/8) = 63/8 = 7,875.