Find the nth term of the geometric sequence.
-5, -15, 45, -135, 405
A) $a _ { n } = 5 \cdot ( - 3 ) ^ { n - 1 }$
B) $a _ { n } = 5 \cdot ( - 3 ) n$
C) $a _ { n } = a _ { 1 } - 3 ^ { n }$
D) $a _ { n } = 5 \cdot ( - 3 ) ^ { n }$

Question

Quizplus · Accepted Answer

The sequence is a geometric sequence with the first term $a_1 = 5$ and common ratio $r = -3$. The nth term of a geometric sequence is given by $a_n = a_1 \cdot r^{n-1}$, which matches option A.

Find the Nth Term of the Geometric Sequence an=5⋅(−3)n−1a _ { n } = 5 \cdot ( - 3 ) ^ { n - 1 }an​=5⋅(−3)n−1

Find the Nth Term of the Geometric Sequence $a _ { n } = 5 \cdot ( - 3 ) ^ { n - 1 }$