Define whether sequence is arithmetic or geometric and write the n-th term formula1) 11,17,23,…2) 5,15,45,…

Litzy Wallace

Answered question

2022-03-27

Define whether sequence is arithmetic or geometric and write the n-th term formula 1) $11,17,23,\dots$ 2) $5,15,45,\dots$

Answer & Explanation

aznluck4u72x4

Beginner2022-03-28Added 16 answers

(1) $11,17,23,\dots$ $17-11=6$, $23-17=6$, thus, $r=6$ and the sequence is arithmetic n-th term: $a+(n-1)d$ $=11+(n-1)6$ $=11+6n-6$ $=6n+5$ (n-th term formula) (2) $5,15,45,\dots$ $\frac{15}{5}=3$ and $\frac{45}{15}=3$, thus, $r=3$ and the sequence is geometric n-th term: $a{r}^{n-1}$ $=5\times {3}^{n-1}$ (n-th term formula)