Question

Recursive sequence/formula?

Answer 1

The following function defines a recursive sequence.

f(0) = -2

f(1) = 8

f(n) = -4•f(n -1) - 3•f(n - 2); for n > 1

Which of the following sequences is defined by this recursive function?

-2, 8, -26, -80, …

-2, 8, -26, 80, …

-2, 12, -44, 180, …

-2, -12, -44, -180, …

Answer 2

@texaschic101

Answer 3

This is what I did: -4 x f(8 - 1) - 3 x f(8 - 2)
-4 x 7 - 3 x 6
-28 - 18
-46

Answer 4

Substitute n = 2, you get:

f(2) = -4f(1) - 3f(0)
= -4(8) - 3(-2)
= -32 + 6
= -26

So we know that the third term, when n=2, will be -26.

Now, substitute n = 3 into the given recusive equation.

Answer 5

So I have f(3) = -4f(2) - 3f(1)?
f(3) = -4(-28) - 3(8)
f(3) = 112 - 24
f(3) = 88

Answer 6

Help @Easyaspi314

Answer 7

right idea, but f(2) = -26 (not -28)

Answer 8

Ohhh my bad

Answer 9

f(3) = -4f(2) - 3f(1)?
f(3) = -4(-26) - 3(8)
f(3) = 104 - 24
f(3) = 80

Answer 10

Thanks so much :)

Answer 11

Could you help me with a few more?

Answer 12

if you make a new post

Answer 13

Okay