Question

Find an explicit rule for the nth term of the sequence. -3, -15, -75, -375, ...

Answer 1

do you have the geometric series equation handy?

Answer 2

Not at the moment, but I'm looking for it!

Answer 3

an = a1r n-1

Answer 4

so you need to find what "r" is. it's basically just the common ration between these numbers.

Answer 5

How do I find the ratio?

Answer 6

divide the two terms of series to find ratio

Answer 7

the ratio is a_2 / a_1

Answer 8

Okay so 5

Answer 9

ya,

so you know the equation, just plug in a_1 and r into it and leave it as an equation for you answer