### Home > INT1 > Chapter 7 > Lesson 7.1.4 > Problem7-48

7-48.

For parts (a) and (b), write a recursive equation using $a_{n}$ notation for each sequence. For parts (c) and (d), write an explicit equation using $t(n)$ notation for each sequence. (For a reminder about sequence notation, see the Math Notes box in Lesson 5.3.2.)

Read Math Notes box in Lesson 5.3.3 on equations for sequences.

1. $108, 120, 132, …$

$a_{1} = 108$
$a_{n+1} = a_{n}+12$

1. $\frac { 2 } { 5 },\frac{4}{5},\frac{8}{5}, ...$

$a_1=\frac{2}{5}$

$a_{(n+ 1)} = 2a_{n}$

1. $3741, 3702, 3663, …$

Is the sequence arithmetic or geometric?
Remember to write an explicit equation.

1. $117, 23.4, 4.68, …$

Is the sequence arithmetic or geometric?
Remember to write an explicit equation.