Write the first four terms for each sequence. State whether the sequence is arithmetic, geometric, or neither.
(a) $a_{n}=(n+1)(n-2)$
(b) $a_{n}=\left(-\frac{1}{4}\right)^{n-1}$
(c) $a_{1}=2, a_{2}=6, a_{n}=2 a_{n-1}-a_{n-2}$, for $n \geq 3$

Question

Quizplus · Accepted Answer

The Answer is (a)

-2,0,4,10

; neither
(b)

1,-\frac{1}{4}, \frac{1}{16},-\frac{1}{64}

; geometric
(c)

2,6,10,14

; arithmetic

Write the First Four Terms for Each Sequence an=(n+1)(n−2)a_{n}=(n+1)(n-2)an​=(n+1)(n−2) (B) an=(−14)n−1a_{n}=\left(-\frac{1}{4}\right)^{n-1}an​=(−41​)n−1 (C) a1=2,a2=6,an=2an−1−an−2a_{1}=2, a_{2}=6, a_{n}=2 a_{n-1}-a_{n-2}a1​=2,a2​=6,an​=2an−1​−an−2​

Write the First Four Terms for Each Sequence $a_{n}=(n+1)(n-2)$ (B) $a_{n}=\left(-\frac{1}{4}\right)^{n-1}$ (C) $a_{1}=2, a_{2}=6, a_{n}=2 a_{n-1}-a_{n-2}$