ECZ 2020 · O-Level Paper 2 · Question 5 — Sequences and Series
The first three terms of a geometric progression are m - 2, m + 1 and m + 7.
(a) Simplify 2 - 18p^23p + 1.[2]
Verified working — step 1
2 - 18p2 = 2(1 - 9p2) = 2(1 - 3p)(1 + 3p)(b(i)) The first three terms of a geometric progression are m - 2, m + 1 and m + 7. Find the value of m.[3]
Verified working — step 1
The common ratio is the same: m + 1m - 2= m + 7m + 1(b(ii)) Find the common ratio.[2]
Verified working — step 1
With m = …(b(iii)) Find the sum of the first 6 terms.[2]
Verified working — step 1
S_n = ar^n - 1r - 1with a = 3 and r = …The full step-by-step working and final answer are included with Premium — checked against ECZ marking standards.
Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.
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