Determine whether the sequence below is a geometric sequence and, if so, find a formula that describes the sequence. 1, 3, 9, 27,

a geometric sequence is a bunch of numbers where you can get from a number to the next number by multiplying the previous number by a certain number

might be confusing so here's an example

1,2,4,8,16

each term is multiplied by 2 to get next term, that number that each term is multiplied by is called the common ratio

formula for geometric sequence is

where is nth term

is first term

r is teh common ratio

n=which term

in our example

1,3, 9, 27, 81

each term is being multiplied by 3 so it is a geometric sequence and thus r=3

also first term is 1 so

so the formula is or in function notation