Question

Find an equation for the nth term of the sequence.

-2, -8, -32, -128, ...

Answer 1

do you see any pattern in that ?

Answer 2

times 4?

Answer 3

that means common ratio r=4
it is A.P or G.P

Answer 4

yes, thats correct!
so your common ratio = r = 4

Answer 5

just use this general formula now
\(\huge a_n = a_1r^{n-1}\)

where a1 = 1st term = -2
r= 4
plug in values!

Answer 6

an = -2 • 4n - 1 ?

Answer 7

if you mean
\(a_n = -2 \times 4^{n-1}\)
then you're correct :)

Answer 8

thx!

Answer 9

welcome ^_^