Question

Write the explicit formula that represents the geometric sequence -2, 8, -32, 128

Answer 1

HI!!

Answer 2

hi

Answer 3

what do you multiply \(-2\) by to get \(8\)?
this is another way of asking what is \(8\div(-2)\)

Answer 4

-16

Answer 5

hmm no

Answer 6

-9

Answer 7

no..

Answer 8

-4

Answer 9

what is 8/2 ?

Answer 10

4

Answer 11

yeah! so here it just has a minus sign extra coz it is..-8/2 so it will be -4

Answer 12

ok?

Answer 13

yeah

Answer 14

so r =-4

Answer 15

are u familiar with this notation?

Answer 16

no i am not

Answer 17

r stand for common ratio of a G.P..

Answer 18

the sequence goes like: a,ar,ar^2,ar^3 and so on..got it?

Answer 19

let
a1= -2

a2= 8

a3 = -32

a4 = 128


find ratio a2/a1 = 8/-2 =

a3/a2 =

a4/a3 =

if u get all above ratios are equal
the above sequence is in geometric sequence

Answer 20

okay thank you

Answer 21

im still lost . do i just do the 4/3= is that what i have to do.

Answer 22

no
a1 means first term

Answer 23

a2/a1 = 8/-2 = -4

a3/a4 = -32/8 =

Answer 24

is it clear

Answer 25

i think so. thank you

Answer 26

here u get ratio = -4
this is called common ratio denoted with 'r'

Answer 27

yeah they all come out as -4

Answer 28

general form of the sequence is

Answer 29

okay thank i will get it

Answer 30

:)

Answer 31

:)