Arithmetic and Geometric Sequences

An arithmetic sequence is a list of numbers where the same number is added each time.

Here's the formula:

tn = t1 + (n-1)d

t1=1st term in sequence

n=term number

d=difference(what's being added)

tn=___ term

A geometric sequence is a list of numbers where the same number is multiplied each time.

Formula time:

tn = r^(n-1)

r=what's being multiplied

Example

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Ex: Is this sequence arithmetic or geometric?

a.) 3, 5, 7, ...

2 is being added each time, so it's arithmetic.

b.) 2, -4, 8, -16...

-2 is being multiplied each time, so it's geometric.