In a progression, the first term is $a$ and the second term is $\frac{a^2}{a + 2}$, with $a$ being a positive constant.
(a)[5]
When the progression is geometric and the sum to infinity equals $264$, determine the value of $a$.
(b)[5]
When the progression is arithmetic and $a = 6$, find the least value of $n$ needed for the sum of the first $n$ terms to be below $-480$.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Apply the recurrence relation $r=\frac{a}{a+2}$” …
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