Find the value of a4 for this geometric series (i’ll add you on discord if you solve my guy and guyetts)

The value of a4 is 6

Step-by-step explanation:

* Lets revise the rule of the geometric series

- There is a constant ratio between each two consecutive numbers

- Ex:

# 5  ,  10  ,  20  ,  40  ,  80  ,  ………………………. (×2)

# 5000  ,  1000  ,  200  ,  40  ,  …………………………(÷5)  

* General term (nth term) of a Geometric series:

- a1 = a  ,  a2 = ar  ,  a3  = ar2  ,  a4 = ar3  ,  a5 = ar4

- an = ar^n-1, where a is the first term , r is the constant ratio

  between each two consecutive terms  and n is the position

  of the number in the series

* Now lets solve the problem

- The rule of the series is  2/9 (3)^n - 1

∴ a = 2/9 and r = 3

- To find a4 put n = 4

∴ a4 = 2/9 (3)^(4 - 1) = 2/9 (3)³ = 2/9 (27) = 6

∴ The series is 2/9 , 2/3 , 2 , 6 ,

* The value of a4 is 6

-7/8

step-by-step explanation:

instead of subtracting you add the -6/8 and -1/8

a=24; b=12

step-by-step explanation:

a/b=2: 1

a=2b

36/(1+2)=12

b=12

a=24