ECZ 2016 · O-Level Paper 2 · Question 5 — Sequences and Series
Question from ECZ 2016 · O-Level Paper 2 · Question 5
(a) Simplify x - 1x2 - 1.[2]
Verified working — step 1
Factorise the denominator: x2 - 1 = (x - 1)(x + 1).(b) The first three terms of a geometric progression are x + 1, x - 3 and x - 1. Find
(b(i)) the value of x,[3]
Verified working — step 1
In a GP consecutive ratios are equal: x - 3x + 1 = x - 1x - 3.(b(ii)) the first term,[1]
Verified working — step 1
The first term is x + 1.(b(iii)) the sum to infinity.[3]
Verified working — step 1
r = x - 3x + 1 = -4/38/3 = -12, and |r| < 1.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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