Mathematics
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OpenStudy (anonymous):
Generate the first 5 terms of this sequence:
f(1) = 0 and f(2) = 1, f(n) = f(n - 1) + f(n - 2), for n > 2.
0, -1, 1, 0, 2
0, 1, 1, 2, 3
0, 1, 2, 2, 3
0, 1, 1, 2, 2
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terenzreignz (terenzreignz):
This is a rather well known sequence :D
\[\Large \left.\begin{matrix}f(1)&f(2)&f(3)&f(4)&f(5)\\0&1&?&?&?\end{matrix}\right.\]
terenzreignz (terenzreignz):
f(n) = f(n-1) + f(n-2)
So what happens when n = 3?
OpenStudy (anonymous):
n=2
OpenStudy (anonymous):
it would be 2 3 4 after that ?
OpenStudy (anonymous):
yes
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OpenStudy (anonymous):
would the answer be C
terenzreignz (terenzreignz):
I don't know, what's f(3)?
Use the fact that f(n) = f(n-1) + f(n-2)
OpenStudy (anonymous):
n-1 would be 2 and n-2 would be 1?
terenzreignz (terenzreignz):
That's good :)
so f(3) = f(2) + f(1)
Which is...?
OpenStudy (anonymous):
6?
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terenzreignz (terenzreignz):
Don't be silly :P
You're already given the values of f(2) and f(1)
terenzreignz (terenzreignz):
\[\Large \left.\begin{matrix}\color{blue}{f(1)}&\color{blue}{f(2)}&f(3)&f(4)&f(5)\\\color{red}0&\color{red}1&?&?&?\end{matrix}\right.\]
OpenStudy (anonymous):
0 1 2 2 3?
terenzreignz (terenzreignz):
I don't know, let's find out together, but step-by-step.
Now, what's f(3) = ?
OpenStudy (anonymous):
2
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terenzreignz (terenzreignz):
How did you get 2?
OpenStudy (anonymous):
just going 1 number less than 3
OpenStudy (anonymous):
since it looks like the others did that
terenzreignz (terenzreignz):
I told you to follow this formula (as it is said in your problem)
f(n) = f(n-1) + f(n-2)
Set n = 3, and find f(3)
OpenStudy (anonymous):
i got 3
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terenzreignz (terenzreignz):
How?
OpenStudy (anonymous):
plugging in 3 where n is
terenzreignz (terenzreignz):
Okay... so how did you get 3?
terenzreignz (terenzreignz):
I don't see how you could get 3 by plugging in n = 3...
OpenStudy (anonymous):
(3-1)=2 + (3-2)=1 and i just added it to 3 i dont get it
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terenzreignz (terenzreignz):
f(n) = f(n-1) + f(n-2)
Please plug in n = 3 again, but be very careful when evaluating.
OpenStudy (anonymous):
what did i do wrong
terenzreignz (terenzreignz):
It's not (3-1) and (3-2) which you add, it's f(3-1) and f(3-2)
which are totally different.
OpenStudy (anonymous):
so what do i do with the f
OpenStudy (anonymous):
you multiply?
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terenzreignz (terenzreignz):
It's a function.
And as I have said before, you ARE given the values of f(1) and f(2)
OpenStudy (anonymous):
i think its C
terenzreignz (terenzreignz):
But why?
OpenStudy (anonymous):
because it looks like thats how the pattern goes am i wrong
OpenStudy (anonymous):
follow pony
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terenzreignz (terenzreignz):
I strongly advise against guessing ^_^
OpenStudy (anonymous):
is my guess wrong
terenzreignz (terenzreignz):
Let's find out.
Starting with you figuring out f(3)
from the formula
f(n) = f(n-1) + f(n-2)
OpenStudy (anonymous):
f(2)=1
OpenStudy (anonymous):
f(1)=0
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OpenStudy (anonymous):
f(3)=2
OpenStudy (anonymous):
so 1+0=1
OpenStudy (anonymous):
what do you think
OpenStudy (anonymous):
what do i think is the answer?
terenzreignz (terenzreignz):
Just f(3) for now. How do you get 2?
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OpenStudy (anonymous):
3-1=2
terenzreignz (terenzreignz):
But why would you do 3-1?
OpenStudy (anonymous):
n-1 u plug in the 3
terenzreignz (terenzreignz):
but n-1 isn't the expression to plug n = 3 in
It's
f(n) = f(n-1) + f(n-2)