Question

Given the geometric sequence where a1=-3 and the common ratio is 9 what is the domain for n

Answer 1

$\bf n^{th}\textit{ term of a geometric sequence}\\\\ a_n=a_1\cdot r^{n-1}\qquad \begin{cases} n=n^{th}\ term\\ a_1=\textit{first term's value}\\ r=\textit{common ratio}\\ ----------\\ a_1=-3\\ r=9 \end{cases}\implies a_n=-3(9)^{n-1}$

for a geometric sequence, the values "n" can take on for it to work, is usually all whole numbers, or positive integers, including 0, or you can say { x | x ∈ ℤ; x ⩾ 0 }