ECZ 2019 · O-Level Paper 2 · Question 2 — Sequences and Series

The geometric progression 4, 8, 16, ...

(a) Simplify 6x^2 - 24x - 2.[2]

Verified working — step 1

6x2 - 24 = 6(x2 - 4) = …

(b(i)) Given the geometric progression 4, 8, 16, ..., find the geometric mean of 256 and 1 024.[2]

Verified working — step 1

The geometric mean of two numbers is the square root of their product.

(b(ii)) Find the 11th term.[2]

Verified working — step 1

a = 4 and r = 84= …

(b(iii)) Find the sum of the first 11 terms.[3]

Verified working — step 1

S_n = …

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.

Have a different question?

Search it — if it is from a past paper or a school mock, chances are we have it worked out, or one that uses the same method.

Search any past-paper question

More Sequences and Series questions from past papers