Arithmetic & Geometric Sequence

Determine if the sequence is arithmetic or geometric.

1.2, 3.5, 5.8, 8.1, 10.4

• Not possible

• Geometric

• Arithmetic

• Algebraic

Find  $a_{12}$  using the information given.  -5, -2, 1, 4, 7,...
 $\ \ \ a_n=a_1+\left(n-1\right)d$  

• 34

• 32

• 30

• 28

Write the expression for the general term  $a_n$  of the arithmetic sequence.
2, 5, 8, 11, ...

•  $a_n=3n-1$  

•  $a_n=3n+1$  

•  $a_n=n^2-3$  

•  $a_n=3n-n$  

Find the indicated term.
 $a_1=\frac{12}{25},\ d=-\frac{1}{10};\ find\ a_9\ \ \ \ \ \ a_n=a_1+\left(n-1\right)d$  

•  $a_9=-\frac{12}{25}$  

•  $a_9=-\frac{10}{25}$  

•  $a_9=-\frac{8}{25}$  

•  $a_9=-\frac{6}{25}$  

Find the number of terms in an arithmetic sequence,


   $-3.4,\ -1.1,\ 1.2,\ 3.5,...,\ 38\ \ \ \ a_n=a_1+\left(n-1\right)d$  

• 10

• 15

• 20

• 25

 $\ \ \ a_n=a_1+\left(n-1\right)d$  Find the indicated term.
 $a_1=-60,\ \ d=5;\ \ find\ a_{50}$  

• 685

• 860

• 680

• 586

Use: $s_n=\frac{n}{2}\left(a_1+a_2\right)$  Evaluate the sum.
 $\sum_{n=1}^{106}\left(-3n+7\right)$  

• -61,271

• -16,271

• -27,161

• -72,161

 $s_n=\frac{n}{2}\left[2a_1+\left(n-1\right)d\right]$  

Use the formula for the following.

The sum  $s_{82}$  for the sequence
-9 -3 +3+9+15+...

• 18,891

• 81,891

• 19,881

• 19,188

Find the nth partial sum indicated for the sequence.
The sum

 $s_{50}$    using        $s_n=\frac{n}{2}\left[2a_1+\left(n-1\right)d\right]$  
(-2) + (-7)  + (-12) +  (-17)  + ...

• -5622

• -6225

• -6522

• -2265

 $a_n$  Write the expression for the general term  

-17, -14, -11, -8

•  $a_n=2n-20$  

•  $a_n=3n-20$  

•  $a_n=2n-23$  

•  $a_n=3n-20$