Which one is the formula for the general term of the arithmetic sequence $$-\dfrac{1}{3},\dfrac{1}{9},-\dfrac{1}{27},\dots$$

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Uniteasy Admin · Accepted Answer

$$-\dfrac{1}{3},\dfrac{1}{9},-\dfrac{1}{27},\dots$$
For  $$a_n =\dfrac{(-1)^n}{3^n}$$
when $$n =1$$, $$a_1 = \dfrac{(-1)^1}{3^1} = -\dfrac{1}{3}  $$
When $$n = 2, a_2 = \dfrac{(-1)^2}{3^2} = \dfrac{1}{9}$$
When $$n = 3, a_3 = \dfrac{(-1)^3}{3^3} = -\dfrac{1}{27}    $$
Therefore, C is the right option

Multiple Choice Question (MCQ)

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