# Crows dropping nut, maths SL portfolioWatch

Thread starter 10 years ago
#1
k guys im kinda doing my second portfolio right now n im kinda stuck on one part of the question

height 1.7 2.0 2.9 4.1 5.6 6.3 7.0 8.0 10.0 13.9
number of drops 42.0 21.0 10.3 6.8 5.1 4.8 4.4 4.1 3.7 3.2

they given us information on crows dropping nut.. with the height and the number of drops.i managed to plot this graph n i get an Hyperbole graph. the question asks

what type of function models the behavior of the graph? explain why you chose this function.create an equation (a model)that fits the graph.

i dont get how to get the equation they asking for. please could someone help me urgently..or explain to me.thanx
0
10 years ago
#2
(Original post by djoe09)
k guys im kinda doing my second portfolio right now n im kinda stuck on one part of the question

height 1.7 2.0 2.9 4.1 5.6 6.3 7.0 8.0 10.0 13.9
number of drops 42.0 21.0 10.3 6.8 5.1 4.8 4.4 4.1 3.7 3.2

they given us information on crows dropping nut.. with the height and the number of drops.i managed to plot this graph n i get an Hyperbole graph. the question asks

what type of function models the behavior of the graph? explain why you chose this function.create an equation (a model)that fits the graph.

i dont get how to get the equation they asking for. please could someone help me urgently..or explain to me.thanx
well from what you said i'd say it was a hyperbolic function - then just use graph transformation....

or am i not understanding the question? xD
0
10 years ago
#3
What does 'cows dropping nut mean?'. Only then will I help you.
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10 years ago
#4
(Original post by Hancock orbital)
What does 'cows dropping nut mean?'. Only then will I help you.
Crows, not cows. Cows are far too sensible to drop nuts and gobble them up quick.
0
10 years ago
#5
Try Ae^kx +/- Be^mx
0
Thread starter 10 years ago
#6
yea i went thru it and it is a decreasing exponential graphso wat u mean by this equation Ae^kx + divide by -Be^mx
0
10 years ago
#7
(Original post by djoe09)
yea i went thru it and it is a decreasing exponential graphso wat u mean by this equation Ae^kx + divide by -Be^mx
You can express hyperbolic functions in terms of real and imaginery exponents - however, it is clearer to the person when you seperate real and imaginarey expoents using multiply or division.

Don't worry about it - there was no need for a hyperbolic function - just He^-kx.
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Thread starter 10 years ago
#8
aite so i jus concentrate on the y = Ae^kx?
0
10 years ago
#9
Just concentrate on y = Ae^kx.
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Thread starter 10 years ago
#10
oh ok thanks a lot... will see how i progress. gotta give it in on Wednesday.will let you know about any other problems..thank you so much
0
10 years ago
#11
Brining back old post, but whatever.
I'm attempting to do this damn portfolio right now.
However I have some problems with that "Crows dropping nuts" part.
First of all I have no idea what they mean by "Define all variables".
I don't have any variables, as I already draw a graph (which does is limited) so I know exact values of all points used to do so. What is even a more disturbing is the whole paramter thing. No one has even told me about it. And I cannot find any information about it.
Nextm what type of function models the behaviour? I'm not that stupid so I know it is hyperbole thing. However I though that this function has equation y = x^(-1) for x>3 (more or less).
But now, after seeing that "He^-kx" function I'm confused.
Anyone willing to give some tips?

Just in case anyone would like to help, I'm giving link to pdf with that page.
http://www.mis-munich.de/pbook/maths...ndCriteria.pdf
0
9 years ago
#12
Yeah i have to do this same investigation too and im not sure what they mean by 'define all variables'. and what does parameters mean either?
0
9 years ago
#13
By "Define all Variables", it should mean simply stating the variables and factors that can affect the dropping of the nut. If you have done physics, chemistry, bio or whatever, reports, it will be similar to "Control of Variables".
This includes stating the dependent and independent variables and what you are assuming, eg. No wind when the nut is dropped.

I'm still doing this so yeah xD Progressive learning.
0
9 years ago
#14
I'm doing the same problem and we were told to do it on the TI-84 calc, but I can't find any stat things that fit the graph. In y = Ae^kx, is that on the calc? And is k just b?
0
9 years ago
#15
Hey I'm doing the same portfolio however im having some problems of my own. does anyone know how were supposed to explain the question: what type of function models the behaviour of the graph? Explain why you chose this function. Create an equation (a model) that fits this graph. ? I have figured out what type of graph it could be based on my knowledge in math but im not sure how were supposed to explain it especially since it was all trial and error on my GDC that gave me the equation. I just kept plugging in numbers and translationing the graph a bit and streching it some. But i dont know how were supposed to explain it. I dont have to show graphs for every step i did do i? please if anyone can help that would be awesome.
thanks
0
9 years ago
#16
im so confused..what would the equation b?
0
9 years ago
#17
You really need to use the STAT function on your GDC, its really easy to do
Press STAT and then edit on the first menu(edit)
read about corellation coefficients( r and rsquared values)
turn on diagnostic on your calculator 2nd function, catalo, scroll, enter on diagnostic on, enter again
Use STAT again but this time go to Tests, it gives you a variety of functions
if you read about corellation coefficiecient you'll know which one to pick
Feel free to rep me please!!
0
9 years ago
#18
(Original post by iNeedA7InBio)
You really need to use the STAT function on your GDC, its really easy to do
Press STAT and then edit on the first menu(edit)
read about corellation coefficients( r and rsquared values)
turn on diagnostic on your calculator 2nd function, catalo, scroll, enter on diagnostic on, enter again
Use STAT again but this time go to Tests, it gives you a variety of functions
if you read about corellation coefficiecient you'll know which one to pick
Feel free to rep me please!!

i did try to look up what correlation coefficients mean, but im not sure i grasped the concept..
0
9 years ago
#19
(Original post by ~kewl~)
i did try to look up what correlation coefficients mean, but im not sure i grasped the concept..

Did you understand the thing about r and r squared values. In essence,the higher the r and r squared values of the function you derive are the more accurate the model/function you derive is. Does that help?
0
9 years ago
#20
oh no i understood that part. i was just wondering how to derive the equation..
0
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