IA Type II -- Population Trends in China

[M1AguRstKin0B]

Ohh... Ok Desy-san

So I would try to comment on the trend on the first graph i have? Basically just do that?

post #308 "Matrices: it's just one way to solve the fastest way I should say, but elimination and substitution will do

Wow I never thought you'd need to do that hmm probably because I'm not doing this portfolio task. So you decide then: logarithmic or exponential. " this is what you told someone before in terms of what functions to use.

Would you highly recommend Matrices? - Would it really make doing your course work that easY? ... I am by the way, still doing the first part of my Coursework, before the KLM formula.

Would it be possible for you to give me examples in using this for the course work? Like a similar table of data with the year but they have different values in them.

[dessskris]

Yes.

For me it's easy if you understand it. Basically you create the matrices and your calculator will give you the answers.

I'm pretty sure I've created such thing, should be somewhere in this thread or maybe in the files section for VIP only.

[M1AguRstKin0B]

The matrices? Yes, I've seen it on this thread

Aight, let me do the Commenting on the trends of the graph first.

Then would it be OK for you to help me choose a function that would be my model?

When it asks the type of function that could model the behaviour of the graph, does it have to be model the precise values of the points in the graph?

[dessskris]

When it asks the type of function that could model the behaviour of the graph, does it have to be model the precise values of the points in the graph?

not necessarily. that's why they ask you to comment on how well your model fits -- because yours might not fit perfectly!

[M1AguRstKin0B]

YAY! I'm free! I have utter confidence in this now! Gonna murk the first part now I hope this logarithmic equation works.

So, then, when it means "Analytically develop one model function that fits the data points on your graph."

How should I go about this?

[dessskris]

okay so you choose logarithmic? start with the general equation, which I think is:

y = a ln(x) +b

if I'm not mistaken. please check with other sources too.

what you're trying to do here is to find the values of a and b algebraically from the data that you have. do you have any idea how you'd go about this? if not please please please think about it first as this is your IA and i'm afraid i'm giving too much help, then come back if you are totally stuck.

[M1AguRstKin0B]

okay so you choose logarithmic? start with the general equation, which I think is:

y = a ln(x) +b

if I'm not mistaken. please check with other sources too.

what you're trying to do here is to find the values of a and b algebraically from the data that you have. do you have any idea how you'd go about this? if not please please please think about it first as this is your IA and i'm afraid i'm giving too much help, then come back if you are totally stuck.

Oh my days! My teacher never taught me that was the general equation for log! The reason why I chose log was because when i saw The function of ln x the graph examples looked very convincing. heh heh. Alright. I will check the general equation online and in some maths books since i am in the library

I do Hence me saying "murk this first part" )

A and B meaning the axis? Because I don't see my sheet mentioning A and B anywhere

What I was thinking of doing is, using those formula and yours, and to think of which values would work to up to each points on the graph individually. Although I was hoping to do something like the Sequences and Series though. Hahaha. If possible...

[dessskris]

it wasn't taught in class!! it's just some general knowledge, this is why you have to do IAs so you actually become more aware of things that are not taught in class and so you do some further research on the subject to gain more knowledge. and of course to make you think critically and creatively. (oh god i'm talking TOK ****)

don't think you'd find it in any math book.

I mentioned a and b in the equation

a and b are constants. that you need to find.

what those formula?

I don't think you'd really work with sequences/series in IA type 2 as they already appear in IA type 1.

[M1AguRstKin0B]

it wasn't taught in class!! it's just some general knowledge, this is why you have to do IAs so you actually become more aware of things that are not taught in class and so you do some further research on the subject to gain more knowledge. and of course to make you think critically and creatively. (oh god i'm talking TOK ****)

don't think you'd find it in any math book.

I mentioned a and b in the equation

a and b are constants. that you need to find.

what those formula?

I don't think you'd really work with sequences/series in IA type 2 as they already appear in IA type 1.

Oh geez Whew... Ok... I need to refresh myself now.

Aight...

Is it? Aww And I've pulled out an SL and HL maths book

if that;s the case, how can I use this equation then?

You have??? Since when??? SO those constants that must be found should make up the values on the graph?

Them ones from the function of ln x. The exponential function. and some laws of log.

Ohh, darn it.

would it be ok to mention that formula you gave me as the function that could model the behaviour of the graph? Then is it ok to use it again for the analytically develop bit?

[dessskris]

SO those constants that must be found should make up the values on the graph?

yes

would it be ok to mention that formula you gave me as the function that could model the behaviour of the graph? Then is it ok to use it again for the analytically develop bit?

yes and yes

[M1AguRstKin0B]

Yay1 I'm gonna keep asking questions by the way to set up what I'm going to do so I can just read through this and work my way in finishing this.

Uhm,so yeah, how do I use the formula you gave me? because my calculator was just flipping out with the Ln(x) in it.

It just hit me, when it asks, "What types of functions could model the behaviour of the graph?" Is it just asking me like in a CHemistry test, "What are the elements in group 1?"

[dessskris]

I don't get what you mean.

if you ever need something, read through this whole thread, you'll be able to find the answers. unless you're skimming.

[M1AguRstKin0B]

I don't get what you mean.

if you ever need something, read through this whole thread, you'll be able to find the answers. unless you're skimming.

Ok, seriously now Desy, let me just ask you this one or two question/s. After this, my next question will be over the weekends.

First, how can I use this y= a ln(x) + b?

Second, can you also show me the equation for Linear, Quadratic and Exponential seeing that I have nearly looked every where online this past weekend and I've got nothing

Please desy. This could also help out for those SL Maths people who might not have done Matrices and 6th Polynomials as well.

[dessskris]

If I said I have explained it before, I have. It's not like I've finished IB and have nothing better to do. I have other works too finish too! It's your IA! What's so difficult about reading this whole thread, if it's for your own good? I don't gain anything from this and I could have chosen not to help anybody if I didn't want to. You've been asking stupid questions tbh, and repeating them over and over! How many times have you asked which function to use? And you don't even put in an effort to search in this thread?!

It's either you don't have enough logic or your brain cells are dead.

SIGH

---

Start by stating the general formula y=a ln(x) +b where a and b are constants.

Choose two sets of values of x and y from the data given in the table. Substitute them into the general equation and then solve the two equations simultaneously to get a and b. You are done.

For God's sake, without having googled those functions you should have enough logic to be able to guess. Or some of the very obvious ones must have been learned in class.

List of Functions

Linear y=mx+c

Quadratic y=ax²+bx+c

Cubic y=ax³+bx²+cx+d

Quartic y=ax⁴+bx³+cx²+dx+e

n^th Polynomial y=axⁿ+bx^n-1+cx^n-2+...+dx²+ex+f

Power y=ax^b

Exponential y=ab^x or y=ae^bx+c

Logarithmic y=aln(x)+b

Sinusoidal y=asin(bx+c)+d

Cos y=acos(bx+c)+d

Tan y=atan(bx+c)+d

Arcsin y=asin^-1(bx+c)+d

Arccos y=acos^-1(bx+c)+d

Arctan y=atan^-1(bx+c)+d

[M1AguRstKin0B]

YAY! I've successfully read through the entire thread which only a small portion of it gave me good hints and tips.

APparently, my brain cells ARE dying. This IA is my kryptonite. And don't worry, after this IA, you won't hear a peep out of me anymore, so just bear with me until next Monday, Desy. Please?

THANKS for the response. I will look through it after my first class.

If I said I have explained it before, I have. It's not like I've finished IB and have nothing better to do. I have other works too finish too! It's your IA! What's so difficult about reading this whole thread, if it's for your own good? I don't gain anything from this and I could have chosen not to help anybody if I didn't want to. You've been asking stupid questions tbh, and repeating them over and over! How many times have you asked which function to use? And you don't even put in an effort to search in this thread?!

It's either you don't have enough logic or your brain cells are dead.

SIGH

Do you hate me?

---

Start by stating the general formula y=a ln(x) +b where a and b are constants.

Choose two sets of values of x and y from the data given in the table. Substitute them into the general equation and then solve the two equations simultaneously to get a and b. You are done.

List of Functions

Linear y=mx+c

Quadratic y=ax²+bx+c

Cubic y=ax³+bx²+cx+d

Quartic y=ax⁴+bx³+cx²+dx+e

n^th Polynomial y=axⁿ+bx^n-1+cx^n-2+...+dx²+ex+f

Power y=ax^b

Exponential y=ab^x or y=ae^bx+c

Logarithmic y=aln(x)+b

Sinusoidal y=asin(bx+c)+d

Cos y=acos(bx+c)+d

Tan y=atan(bx+c)+d

Arcsin y=asin^-1(bx+c)+d

Arccos y=acos^-1(bx+c)+d

Arctan y=atan^-1(bx+c)+d

When you said "solve the two equations simultaneously , basically it means do a sim. equation "?

e.g.

y = 1950 ln(x) + 554.8

y = 1955 ln(x) + 609.0

-Like that? SOrry, I just wanted to clarify it.

[dessskris]

GOD!!!

if your time and population are x and y respectively, why would you substitute them as a and b??? and anyway I said "solve for a and b"!!!

[M1AguRstKin0B]

Desy desy desy, you know the analytically develop part? How can I show this in MS Word? Like, is this the working out/pen and paper bit?

[dessskris]

OH MY GOD I really really wish somebody else who had done this portfolio can explain it to you because I'm just sick of repeating everything!!! I have just explained it to you a few hours ago why are you asking me again????? this is what I don't like! it just seems like you don't appreciate what I said. all the information comes in through your right ear, passes by and goes out through your left ear after that, without having visited your brain or being digested.

[M1AguRstKin0B]

Would anyone care to explain to my why, when I use the exponential function, erm, lemme show you guys instead...

e.g.

(10)(1)¹⁹⁵⁰=10

So yeah, that's what basically happened which left me dumbfounded. Have I missed something when 1 is powered to 1950??? Shouldn't it be something like 1950 and not 1?

I am analytically developing a model based on this one...

y=ab^xwhch is the exponential function.

And x = time, which is the years basically.

So then, for example if I do y = 554.8 x 1¹⁹⁵⁰

would that be able to replicate the graph? Coz a friend of mine told me it would end up being a vertical line from y = 1 onwards.

Edited July 28, 2011 by Summer Glau

[dessskris]

SIGH.

(10)(1)¹⁹⁵⁰=10

this expression is correct. use your calculator. 1 to the power of anything is still 1. imagine multiplying 1 by a thousand more of 1s. and so 10x1=10.

look, if x is your time and y is the population, you substitute x and y into your general equation! giving something like 103=ab¹⁹⁴⁵. why did you substitute a and x??? how many times do I have to repeat this??? and you don't come up with b that way. you should be able to think creatively and critically. if it's x, it's x. it's not a or b, or y. if your friend told you something, go check it for yourself and see if it's true or not. you're not going to write in the IA "my friend said b is 1 so my equation is this." prove it, mathematically.

or you probably should have done studies.