Can someone help?!

Question

0

530

2

Please help me with these questions, thanks :)

#1

#2

#3

#4

I'm not at all good with sequences, so help with the above questions would be greatly appreciated. thanks

Guest Mar 21, 2019

CPhill · Answer 1 · 2019-03-21T04:42:39

First one :

a_n = (2/5)(5)^{n - 1}

Recursive rule : a₁ = 2/5 a_n = 5a_n-1

Second one :

a₁ = 2 an = (1/3)a_n-1

Explicit Rule : a_n = 2(1/3)^n-1

Third one

6, -18, 54, -162 [ note that the common ratio = -3 ]

Recursive Rule : a₁ = 6 a_n = (-3)a_n-1

Fourth one : 9, 6, 4, 8/3

The common ratio is : 6 / 9 = 2/3

Explicit Rule : a_n = 6(2/3)^n-1