### Home > CCG > Chapter 5 > Lesson 5.1.2 > Problem5-19

5-19.

Examine each sequence below. State whether it is arithmetic, geometric, or neither. For the sequences that are arithmetic or geometric, find the formula for $t(n)$ or $a_n$.

Are the sequences decreasing at a constant rate?

1. $100$, $10$, $1$, $0.1$, $\dots$

The equation for a geometric sequence is:
$a_n=a_1·b^{(n-1)}$.

$a_n=100\left(\frac{1}{10}\right)^{(n-1)}$

1. $0$, $-50$, $-100$, $\dots$

Refer to the Math Notes box in Lesson 4.1.3 for more help.