IA Type II -- G-Force Tolerance

[Tommy.D]

Is power function the right answer? since I saw there were a lot of people used Log function as their final answer. And i should have 2 equations by the time i finish the project right? One for horizontal g-force, and one for vertical? Also, when it asks to "Discuss the implications of your model in terms of G-forces acting on a human being" .. I really dont know what i should talk about.

Yes it is. Logarithm fits the shape but not as well as a power function does it's better to model a power function than a logarithm function I suppose.

Umm 3 actually:

1. One for Gx, analytically modelled
   
2. Another one for Gx, modelled using technology
   
3. One for Gz, modification of either the first or the second function

That part, describe the graph in terms of G-force. Like maybe if the force is greater, human beings can tolerate it for a shorter period of time. Or maybe if the force exceeds this amount, human beings cannot tolerate it (asymptote). Something along those lines

Desy, i have a really dumb question. So i got 2 equations from 2 sets of values(3,9) (10,6) which are 6=a*10^b, 9=a*3^b . times ln for both sides i get b=ln6/lna10, and b=ln9/lna3. I then tried set these equations equal each other, ln6/lna10=ln9/lna3, But i dont know how to go from there.

[evanjelly]

No, its all good. So for the first part it says to define variables and parameters and any constrint. what specifically do i have to say? Also, ater plotting the data in excel, i found out the its actually a power function, and it asks to find an equation(or a model) to fit the data, do i have to create a power fucntion by hand or do i just use the one generated from excel? Thanks.

Sorry I guess I'm taking too long to write a reply!

Umm I am not that sure about parameters actually but for that part you should mention what P and t represent (population and time) and roughly their domains if possible. After that once you start modelling you can introduce the parameters there. That is what I would do. However I am not so sure either sorry!

Do not use excel for that part. Model one algebraically

Start with the general equation y=ax^b then substitute in 2 sets of values of x and y and solve for a and b simultaneously

The data I've been given has created a scatter graph that with a curve seems to resemble a curve created by a power function. I immediately thought of y=x-1, it mimics the overall trend but does not intersect all of the points. Obviously the power function comes in the form of y= xab, right ?

So I imput the x and y values of the points (1,11) and (10, 6)... i then made them equal one another; ab-11 = 6ab-10 and then I tried to work it out I'm left with -0.2 = ab....so now what ?

Any help would be greatly appreciated as I'm already late handing this in!!

[dessskris]

Desy, i have a really dumb question. So i got 2 equations from 2 sets of values(3,9) (10,6) which are 6=a*10^b, 9=a*3^b . times ln for both sides i get b=ln6/lna10, and b=ln9/lna3. I then tried set these equations equal each other, ln6/lna10=ln9/lna3, But i dont know how to go from there.

Nah it's not a dumb question you better ask than going wrong

Ok I cannot work it out for you but I can give you an example with different numbers:

After that I suppose you know how to find b

Just do it similarly to my method

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@evanjelly wrong equation.. y=ax^b

[rissyrissa]

hey guys, ive been working on this and does anyone know what to do with the R squared value?

thank you so much.

[rissyrissa]

what do i do with the r squared value???

thanks.

[DaaeDore]

Thanks!! That helped a bunch. Mine is due this week. I think by Friday. I am not sure lol. I think she, my math teacher, said we are going to work on it during class. She is going to teach us how to copy the screen of the Graphing Calculator onto a Word Document.

So... how do you copy the calculator screen onto a Word doc?

[dessskris]

So... how do you copy the calculator screen onto a Word doc?

if you use Windows press this PrtSc SysRq button on your keyboard and then paste in your Word document

or with Windows 7 use Snipping Tool!

or with TI software click capture and copy the image to your Word doc

[CristinaV]

Sweet. My posts got deleted when the server was changed, so I don't know if any of you replied to the last one about the logarithmic function. So here it goes again:

What would make you think that the graph with the data points is like a logarithmic function? Without doing any calculations, just observing.

Oh and by the way, if I do use the function y = a + b*ln(x), would you call that a logarithmic function... or a natural logarithm function... or what?

[zeuble]

Hey

So I have a few queries:

Am i supposed to provide manual working out for the equation?

I mean should I try finding out the equation by hand before using excel and the r2 formula, etc.

If so, then how do I explain why i chose to test if its a power/exponential graph?

or to make it easier should i use excel, come up with an equation

then say "to test validity" try it by hand? like sub some points in?

Also,

When it says

"On a new set of axes, draw your model function and the original data points. Comment on any differences."

How do I graph 2 graphs on 1 graph (if that makes sense ) Would i have to use graph paper?

or can you do that on excel and im just being stupid?

Thank you! :DDD

[IBstudent101]

Thanks for defining the parameters; that definitely helped a ton.

I'm having trouble deriving the equation (although, of course, I can/have easily obtained it using PowerRegression), how can it be derived? Is it using the points (I think somebody mentioned this above)?

Also, just to clarify, "using technology" means you can legitamately use a Regression, without having to derive or anything, correct?

Yes you can use technology as far as I know (a.k.a. your calculator) but you have to state in your portfolio that you used the calculator by using the term "GDC" (graphing display calculator).

That is what my teacher told me.

[DaaeDore]

So... how do you copy the calculator screen onto a Word doc?

if you use Windows press this PrtSc SysRq button on your keyboard and then paste in your Word document

or with Windows 7 use Snipping Tool!

or with TI software click capture and copy the image to your Word doc

Would you need a cable or wire connecting the computer and computer? I'm very bad with technology.

Thank you!

[IBstudent101]

Hey

So I have a few queries:

Am i supposed to provide manual working out for the equation?

I mean should I try finding out the equation by hand before using excel and the r2 formula, etc.

If so, then how do I explain why i chose to test if its a power/exponential graph?

or to make it easier should i use excel, come up with an equation

then say "to test validity" try it by hand? like sub some points in?

Also,

When it says

"On a new set of axes, draw your model function and the original data points. Comment on any differences."

How do I graph 2 graphs on 1 graph (if that makes sense ) Would i have to use graph paper?

or can you do that on excel and im just being stupid?

Thank you! :DDD

Actually I do think on Excel you can do two graphs at once. But you can also do it on www.graphsketch.com and enter two equations in and press "Plot mutiple graphs" I believe. it's really really easy to use! Good luck figuring out this mess!!!

[dessskris]

Hey

So I have a few queries:

Am i supposed to provide manual working out for the equation?

I mean should I try finding out the equation by hand before using excel and the r2 formula, etc.

If so, then how do I explain why i chose to test if its a power/exponential graph?

or to make it easier should i use excel, come up with an equation

then say "to test validity" try it by hand? like sub some points in?

Also,

When it says

"On a new set of axes, draw your model function and the original data points. Comment on any differences."

How do I graph 2 graphs on 1 graph (if that makes sense ) Would i have to use graph paper?

or can you do that on excel and im just being stupid?

Thank you! :DDD

For the very first part, you must work out the function mathematically. Please note that in the 2nd page you are asked to use technology to get a function.

So at first state which function you are going to model and the reasons why. Then state the general formula and get a function. Next plot it on the same axes with your data points. Comment on how well it fits.

Then you may use GDC or graphing software or excel to get another function. You may talk about R² value whatsoever... Then comment on how well it fits too.

When explaining why you choose to model a type of function, mention its characteristics in terms of the shape or maybe the existence of an asymptote, etc...

That is one of a thousand reasons why I do not recommend people to use excel for their Math portfolio. If you have y=x² and you want to plot it with a set of data, you cannot. Or can but you have to put in the points one by one, manually. I know how to plot 2 graphs on the same axes in excel but I don't know how to explain it b/c it's complicated unless you have learnt the basics of excel and you can grasp what I am saying (b/c even I explain to my friend, in front of her with the computer, she still doesn't understand. how do you expect an online text tutorial to help? lol)

So I recommend using your GDC, especially if you have TI that would help a lot.

---

Would you need a cable or wire connecting the computer and computer? I'm very bad with technology.

Thank you!

What calculator do you have? I have TI-Nspire and I don't need to connect it with my computer because its CD contains a computer software that is independent of the actual GDC, so I can use it without plugging the GDC into my laptop. But if I have already done everything in my GDC, I can just connect it with a USB cable to my laptop, open the software and the document can be open there.

I guess it might be the same for other TI calculators, albeit I am not that sure.

[IBstudent101]

Would you need a cable or wire connecting the computer and computer? I'm very bad with technology.

Thank you!

If you have the program "Microsoft Onenote" on your computer (quick check can confirm this) pres the Windows key on your keyboard and press s. Then s. I believe lol, and then you can crop what you want on the screen in front of you and it will transfer that image onto Microsoft Onenote. From there you can click on the image and save it to your computer. Hope this helps

[DaaeDore]

What points did you use to calculate your constants in the equation? Would it be all right to use the first and last points (farthest apart) for each function and then test them in each point to check?

I have determined the a-values (for the formula y=a*x^b) in both functions using one point from each funtion. Then, I plugged the resulting a-values and other x- and y- values into the formula to solve for the b-values using all the other points. The trouble is that the b-values I found each time were almost always very close, but at both of the points where x=3 (so at one point in each function), the b-value I found was quite different. How do you account for this and how do I deal with it in my report?

I hope my questions make sense.

[zeuble]

For the very first part, you must work out the function mathematically. Please note that in the 2nd page you are asked to use technology to get a function.

So at first state which function you are going to model and the reasons why. Then state the general formula and get a function. Next plot it on the same axes with your data points. Comment on how well it fits.

Then you may use GDC or graphing software or excel to get another function. You may talk about R² value whatsoever... Then comment on how well it fits too.

When explaining why you choose to model a type of function, mention its characteristics in terms of the shape or maybe the existence of an asymptote, etc...

That is one of a thousand reasons why I do not recommend people to use excel for their Math portfolio. If you have y=x² and you want to plot it with a set of data, you cannot. Or can but you have to put in the points one by one, manually. I know how to plot 2 graphs on the same axes in excel but I don't know how to explain it b/c it's complicated unless you have learnt the basics of excel and you can grasp what I am saying (b/c even I explain to my friend, in front of her with the computer, she still doesn't understand. how do you expect an online text tutorial to help? lol)

So I recommend using your GDC, especially if you have TI that would help a lot.

Ah I see!

So you recommend finding two equations, one by hand and one by technology? (well i guess it states that we have to)haha

Thanks

btw

i have tried finding reasons to show why i used a ---- function. but i cant find any substantial arguments. Would you be able help on that part?

Thanks a lot

[dessskris]

What points did you use to calculate your constants in the equation? Would it be all right to use the first and last points (farthest apart) for each function and then test them in each point to check?

I have determined the a-values (for the formula y=a*x^b) in both functions using one point from each funtion. Then, I plugged the resulting a-values and other x- and y- values into the formula to solve for the b-values using all the other points. The trouble is that the b-values I found each time were almost always very close, but at both of the points where x=3 (so at one point in each function), the b-value I found was quite different. How do you account for this and how do I deal with it in my report?

I hope my questions make sense.

Mmm it doesn't matter much but I suggest choosing one point in the middle of the (almost) vertical line and the other point in the middle of the (almost) horizontal line. I don't know how to say it but you know what I mean, right?

And what do you mean by in both functions? Gx and Gz? For the last part?

Look, you do not compare the values of a and b in Gx and Gz but you compare the model functions in Gx and Gz. Maybe the shape, the asymptote, etc... but not each constant in the function.

---

Ah I see!

So you recommend finding two equations, one by hand and one by technology? (well i guess it states that we have to)haha

Thanks

btw

i have tried finding reasons to show why i used a ---- function. but i cant find any substantial arguments. Would you be able help on that part?

Thanks a lot

Yeah, not only recommended but you have to!

You are welcome!

Sorry I can't help much on that part, though. I didn't do this task that's why. But if you could PM me the type of function you want to model and what reasons you have found so far, I can try to give you some more ideas.

All other questions go into this thread, though. Just want them to be sent through PM so that noone else can't read it (b/c it's your answer)

[IBstudent101]

I am really confused on what exactly consists of parameters and constraints.

For parameters I was going to write on how time can't be negative and how G-force will not go lower than 0 ....I'm not sure what else

[dessskris]

I am really confused on what exactly consists of parameters and constraints.

For parameters I was going to write on how time can't be negative and how G-force will not go lower than 0 ....I'm not sure what else

I think that's all. or at least all that are obvious I am not sure though since I didn't do this task. I think there is a minimum value for each of x and y, right? (b/c of asymptote). state them if those values aren't zeroes.

[HiddenDreamer]

Is it assumed that we will use technology for the whole portfoilio?

If the question doesn't say 'using technology' then does that mean we can't??

Do we have to hand work anything out?? For e.g. the equation, or can we just use Excel??

On the checklist we got of what to do it says: "Where possible, assignments should be word processed using a computer. Graphs should be computer generated." For the equation you need to use appropriate symbols so writing x^2, 5*x will make you lose marks. I am using Math Type and TI Interactive (you can get a trial for both) they are very helpful.