Question

Find an explicit rule for the nth term of the sequence.

1, 3, 9, 27, ...

(a) an = 1 • 3n + 1

(b) an = 3 • 1n - 1

(c) an = 1 • 3n - 1

(d) an = 1 • 3n

Answer 1

\[1, 3, 9, 27, ...\]
common ratio is 3
\[(3) \times 1 = 3\]
\[(3) \times 3 = 9\]
\[(3) \times 9 = 27\]

Answer 2

\[a _{n} = a _{1} \times r ^{n -1}\]
\[a _{n} = 1 \times 3 ^{n -1}\]

Answer 3

so i believe you made a mistake and did not write your choices in the correct notation, but based on my intuition, I believe your answer is C.