Find a formula for the nth term of the sequence.
-6, -6, 6, -6, 6 (6's with alternating signs)
A) $a _ { n } = 6 ( - 1 ) ^ { n + 1 }$
B) $a _ { n } = 6 ( - 1 ) ^ { n }$
C) $a _ { n } = 6 ( - 1 ) ^ { 2 n + 1 }$
D) $a _ { n } = 6 ( - 1 ) ^ { 2 n - 1 }$

Question

Find a formula for the nth term of the sequence.
-6, -6, 6, -6, 6 (6's with alternating signs) 
A) $a _ { n } = 6 ( - 1 ) ^ { n + 1 }$
B) $a _ { n } = 6 ( - 1 ) ^ { n }$
C) $a _ { n } = 6 ( - 1 ) ^ { 2 n + 1 }$
D) $a _ { n } = 6 ( - 1 ) ^ { 2 n - 1 }$

Quizplus · Accepted Answer

The sequence alternates between positive and negative 6's, so the formula must include a (-1) raised to a power. Since the sequence starts with a positive 6, we use (-1)^(n+1) instead of (-1)^n to make the first term positive. Therefore, the formula for the nth term is a_n = 6(-1)^(n+1).

Find a Formula for the Nth Term of the Sequence an=6(−1)n+1a _ { n } = 6 ( - 1 ) ^ { n + 1 }an​=6(−1)n+1

Find a Formula for the Nth Term of the Sequence $a _ { n } = 6 ( - 1 ) ^ { n + 1 }$