The first three terms of an infinite series are ${16,x,9}$. Find the value(s) of $x$, if the ser

Question

The first three terms of an infinite series are ${16,x,9}$. Find the value(s) of $x$, if the series is geometric, arithmetic.[3] If all the terms in part (i)(a) are positive, calculate its sum to infinity.[2] Given that the sum of the first $n$ terms in part (i)(b) is less than $-64$, find the least value of $n$.[3]

Accepted Answer

(i)(a) $x=12$ or $x=-12$ (i)(b) $x=\dfrac{25}{2}$ (ii) $S_\infty=64$ (iii) $n=13$

2021 DHS Promo Q4

2021 DHS Promo Q4

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