Question

can someone please help??? I don't understand this!!?? :(
Barry has been watching the geese that live in his neighborhood. The number of geese changes each week.



n f(n)
1 56
2 28
3 14
4 7


Which function best shows the relationship between n and f(n)?
f(n) = 28(0.5)^n

f(n) = 56(0.5)^n-1

f(n) = 56(0.5)^n

f(n) = 112(0.5)^n-1

Answer 1

Maybe something that starts at 56 and cuts in half each week?

Answer 2

If you are totally lost, try each choice with n=1
according to your table, when n is 1, the answer should be 56

can you figure out
28(0.5)^n when n is 1?
in other words, what is
\[ 28 \cdot 0.5^1 = 28 \cdot \left(\frac{1}{2}\right)^1 =?\]

Answer 3

it would be 24

Answer 4

ooh, 28/2 = 14 But that is still not 56. so the first choice is not correct.

Answer 5

oh yeah that is what I mean

Answer 6

can you try the 2nd choice?

Answer 7

with n=1 again????

Answer 8

I would write 0.5 as ½

with n=1 then n-1 is 0
so you simplify
\[ 56 \cdot \left(\frac{1}{2} \right)^0 \]

Answer 9

This one requires you to *remember* anything to the zero power is 1
so 2^0 is 1
3^0 is 1
pi^0 is 1

it always works (except for 0^0 which is not defined)

Answer 10

because 1/2 times 0 = 0 and 0 times 56 =0
so its not the 2nd choice

Answer 11

but we are not doing 2*0
we are doing 2^0
that is a totally different thing. re-read what I posted up above.

Answer 12

*remember* anything to the zero power is 1
so 2^0 is 1
3^0 is 1
pi^0 is 1

it always works (except for 0^0 which is not defined)

Answer 13

oh yeah sorry :)
so it would be 28
so not the answer

Answer 14

go slowly
\[ 56 \cdot \left(\frac{1}{2} \right)^0 \]
replace (½)^0 with what ?

Answer 15

using *remember* anything to the zero power is 1

Answer 16

oh sorry
I was really confused
I replace 1/2^0 with 1
so the answer is 56
which is the answer

Answer 17

but now I get it
if anything has a power of 0 it is automatically 1

Answer 18

it is a possible answer. we should check one more value just in case they are trying to trick us.

let's try n=2. the table says we should get 28

what is
\[ 56 \cdot \left(\frac{1}{2}\right)^{n-1} \]
when n is 2 ?

Answer 19

*** if anything has a power of 0 it is automatically 1***
with the except of 0^0 which is not defined.

we could make sense of it, but not now.

Answer 20

replace the n with 2 and figure out 2-1 for the exponent

Answer 21

1/2^2-1
I would get 1/2^1
which stays 1/2
56*I/2 equals 28

Answer 22

so its not the answer

Answer 23

2nd is the answer @MilenaSaeger

Answer 24

I thought its not. im confused now

Answer 25

it's sure @MilenaSaeger

Answer 26

can u explain why

Answer 27

there's no confusion in it ... ))

Answer 28

hmmm ohk ))

Answer 29

f(1) = 56*(1/2)^(1-1) =56*(1/2)^0 = 56*1 =56;
f(2) = 56*(1/2)^(2-1) = 56*(1/2)^1 = 28;
f(3) =(56)*(1/2)^(3-1)=56*(1/2)^2 = 56*(1/4) =14 and so on ...
hence true ))) :p

Answer 30

@MilenaSaeger :)

Answer 31

????/ r u dere ?????////// @MilenaSaeger

Answer 32

sorry I just had to walk one of my dogs.

oh ok well, thank you two @phi and @princeharryyy

Answer 33

u r welcome :p

Answer 34

can u help me with one more??

Answer 35

Zoe keeps track of the miles per gallon her car gets per week. She has accumulated the following data:

(1, 24), (2, 24.38), (3, 24.76), (4, 25.14)

What is the common difference or ratio?

The common difference is 0.38.

The common difference is 0.76.

The common ratio is 0.99.

The common ratio is 1.02.



I think it is D

Answer 36

0.38

Answer 37

for increase of 1 in x coordinate y increases by 0.38

Answer 38

oh ok thank u

Answer 39

or u can say for every x, f(x) that is y increases by 0.38

Answer 40

but how did u got 1.02

Answer 41

@MilenaSaeger

Answer 42

idk I guessed cause x increased by 1 and y was multiplied by 2. oh nvr mind it only multiplied by 2 once. all the other times it just added 0.38

Answer 43

i just kinda guessed and used a little common sense

Answer 44

ohk ))))

Answer 45

a bit wrong )))) no big deal

Answer 46

ok thank u

Answer 47

welcome :)