Mathematics 9709 · AS & A Level · Series

Series — practice question

The 1st, 2nd and 3rd terms of a geometric progression are, in order, the 1st, 9th and 21st terms of an arithmetic progression. The 1st term of each progression is $8$, and the common ratio of the geometric progression is $r$, where $r \neq 1$.

(i)[4]

Calculate the value of $r$.

(ii)[3]

Calculate the 4th term of each progression.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Sets up GP and AP equations correctly” …

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Step-by-step worked solution
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