ECZ 2021 · GCE Paper 2 · Question 1 — Sequences and Series
Question from ECZ 2021 · GCE Paper 2 · Question 1
(a) Simplify a2 x2 - b2 y2ax + by.[2]
Verified working — step 1
a2 x2 - b2 y2 is a difference of two squares: (ax - by)(ax + by).(b) Given the geometric progression 4, 2, 1, ..., find
(b(i)) the 7th term,[2]
Verified working — step 1
a = 4 and r = 24 = 12.(b(ii)) the sum of the first 9 terms.[3]
Verified working — step 1
Sn = a1 - rn1 - r with a = 4, r = 12:(c) Find the geometric mean of 196 and 15 625.[2]
Verified working — step 1
The geometric mean of two numbers is the square root of their product.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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