Question

Write the recursive formula for the geometric sequence.

a1 = -2 a2 = 8 a3 = -32

A. an = -4 + an-1

B. an = -2 + an-1

C. an = -2 • an-1

D. an = -4 • an-1

Answer 1

@Yttrium

Answer 2

@Mandre

Answer 3

@Yacoub1993 if you know the definition of geometeric sequence, you can easily get the answer to this problem. :D
so, do you have idea on what is it?

Answer 4

@Yttrium no i have no idea

Answer 5

Just be reminded that geometric sequence is a sequence following a pattern of multiplying a fixed amount times each term to arrive at the next term.

Answer 6

didnt get it

Answer 7

You can actually do like this
a3/a2
a2/a1
See. If they arrive at a common answer.

Answer 8

then

Answer 9

What happen, do you find common answer?

Answer 10

no dont know how to continue

Answer 11

I mean you divide a3 by a2. After that divide a2 by a1. And see if you find a common answer.

Answer 12

Do you get it @Yacoub1993 ?

Answer 13

lol no how should i divide a3 with a2 or if i divide is it 1.5

Answer 14

confused

Answer 15

a1 = -2
a2 = 8
a3 = -32

If you divide a3 by a2 it's like -32/8 and just do dividing a2 by a1

Answer 16

ohh -4

Answer 17

both are -4 @Yttrium

Answer 18

Nice! You've got it, that is what we call a common ratio (denoted by r) wherein to find the nth term, we need to multiply it by -4.
So I will just give you the general formula in geometric series and let us see if you can answer it correctly.
\[a _{n} = r (a _{n-1})\]

Answer 19

i mean geometric sequence