Question

Find f(5) for this sequence:

f(1) = 2 and f(2) = 4, f(n) = f(1) + f(2) + f(n - 1), for n > 2.

f(5) = ______
@sleepyjess

Answer 1

Ok, from what I found, just ignore the n > 2

Answer 2

f(n) = f(1) + f(2) + f(n - 1)

n = 5? since we are finding f(5)

f(5) = f(1) + f(2) + f(5-1)
f(5) = f(3) + f(4) = 7????

Answer 3

If we know that f(1) = 2, and f(2) = 4, can you substitute in those numbers to find f(3)?

Answer 4

unless f(1) and f(2) is 2 and 4

Answer 5

This is a recursive formula, we need to do f(3), then f(4), and finally f(5).

Answer 6

f(3) = 2 + 4 + f(2), we know that f(2) = 4, so f(3) = 2 + 4 + 4

Answer 7

oh i see

Answer 8

so f(3) = 10

now for f(4)
f(4) = 2 + 4 + f(4 - 1)
f(4) = 6 + f(3)
f(4) = 6 + 4 + 10
f(4) = 20?

Answer 9

Yep, then for f(5)?

Answer 10

OOPS not 6

Answer 11

Wait nvm so f(5) = 30?

Answer 12

just 6 + 10 for f(4)

Answer 13

ok so I did to a typo, haha f(4) = 16

Answer 14

that would make f(5) = 22

Answer 15

Yep, f(4) = 16

Answer 16

Yes! :D

Answer 17

hehe, yay

Answer 18

thanks!

Answer 19

Also,
\({\huge\color{black}{\bigstar}\color{black}{\hspace{2pt}\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}~\color{black}{\hspace{4pt}\bigstar}\color{black}{\bigstar}~\color{black}{\hspace{6pt}\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\hspace{1.5pt}\bigstar}\color{black}{\hspace{1.5pt}\bigstar}}{\hspace-321pt\huge\color{red}{\bigstar}\color{orange}{\hspace{2pt}\bigstar}\color{goldenrod}{\bigstar}\color{yellow}{\bigstar}\color{lightgreen}{\bigstar}\color{green}{\bigstar}\color{turquoise}{\bigstar}~\color{royalblue}{\hspace{4pt}\bigstar}\color{purple}{\bigstar}~\color{#00bfff}{\hspace{6pt}\bigstar}\color{#00bfff}{\bigstar}\color{#00bfff}{\bigstar}\color{#11c520}{\bigstar}\color{#11c520}{\hspace{1.5pt}\bigstar}\color{#11c520}{\hspace{1.5pt}\bigstar}}\\\huge\bf\color{black}W\color{black}E\color{black}{\hspace5ptL}\color{black}{\;C}\color{black}{\;O}\color{black}M\color{black}{\,E~\;}\color{black}{\hspace{4.2pt}T}\color{black}{\:O}~~\color{black}{\hspace{4pt}Open}\color{black}{Study}\hspace-321.8pt{\huge\bf\color{red}W\color{orange}E\color{goldenrod}{\hspace5ptL}\color{yellow}{\;C}\color{lightgreen}{\;O}\color{darkgreen}M\color{turquoise}{\,E~\;}\color{royalblue}{\hspace{4.2pt}T}\color{purple}{\:O}~~\color{#00bfff}{\hspace{4pt}Open}\color{#11c520}{Study}}\\\huge\color{black}{\bigstar}\color{black}{\hspace{2pt}\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}~\color{black}{\hspace{5pt}\bigstar}\color{black}{\bigstar}~\color{black}{\hspace{6pt}\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\bigstar}\color{black}{\hspace1.5pt\bigstar}\color{black}{\hspace{1.5pt}\bigstar\hspace-321.8pt{\huge\color{red}{\bigstar}\color{orange}{\hspace{2pt}\bigstar}\color{goldenrod}{\bigstar}\color{yellow}{\bigstar}\color{lightgreen}{\bigstar}\color{green}{\bigstar}\color{turquoise}{\bigstar}~\color{royalblue}{\hspace{5pt}\bigstar}\color{purple}{\bigstar}~\color{#00bfff}{\hspace{6pt}\bigstar}\color{#00bfff}{\bigstar}\color{#00bfff}{\bigstar}\color{#11c520}{\bigstar}\color{#11c520}{\hspace1.5pt\bigstar}\color{#11c520}{\hspace{1.5pt}\bigstar}}}\\\small\cal Made~by~@sleepyjess\)

Answer 20

No problem! :D

Answer 21

i been on OS as long as my sister. i'd always get all the IP blocked for making accounts and all throughout the time :D

Answer 22

oh lol

Answer 23

haha, yeah

i don't do that anymore cause i actually need help now

Answer 24

What math are you taking? Algebra 2?

Answer 25

Yeah, spammer >=(
Ahaha

Answer 26

no algebra 1

Answer 27

oh lol

Answer 28

haha i dont wanna spam anymore

Answer 29

i retired

Answer 30

I see o-o

Answer 31

Don't worry Kay ;) I hate functons too

Answer 32

algebra 1, feel free to tag me :)

Answer 33

ok :D

Answer 34

thanks!

Answer 35

woohoo lesson 3.04 doesn't need to be done
just told me that

Answer 36

Aaha, congrats =)

Answer 37

haha :)

Answer 38

you doing FLVS?

Answer 39

yeah it was a lesson review i didn't understand too much

Answer 40

I've got you there :) Just wait until you get to pre-calc, they explain even less

Answer 41

ouch hate it when lessons do that

and the civics course i took last year didn't explain nothing :(