Guest rod4eva Posted January 12, 2012 Report Share Posted January 12, 2012 there's a method with matrices that can help you get the equations more accurately... though its hard work... Reply Link to post Share on other sites More sharing options...
Ckbrady Posted February 16, 2012 Report Share Posted February 16, 2012 okay i am so lost.many questions for someone to answer PLEASE like really soon1. isn't everyone's equation going to equal the same thing2. is it easiest to find the equation by splitting it up into three sections?3. how do you plug it into the calculator because years comes out weirdly when trying to graph it4. does anyone know how to find a, b, c, d in a detailed explanation? (ive read all these posts and they are not helpful)5. should i do a different task like g-force because the fish production seems REALLY hard6. if you know the equation can you just please tell me...this is so ridiculously hard.thanks so much. Reply Link to post Share on other sites More sharing options...
helenacarreras Posted March 18, 2012 Report Share Posted March 18, 2012 Hey everyone, i'm kind of desperate right nowI have no clue to to even start it, i read almost everything but im still confused, i have no idea how to make up a equation and create the model, im using autograph, could anyone help me!?!? pleeeasethanks!Helena Reply Link to post Share on other sites More sharing options...
ibsurvivor Posted March 20, 2012 Report Share Posted March 20, 2012 This thread seems kind of dead but i was wondering if anyone could explain how to produce a single model from the three seperate functions? I have analytically developed a function for each of the tables but I'm stuck as to what I'm supposed to do now. Any help would be greatly appreciated. Reply Link to post Share on other sites More sharing options...
chrnomyuu Posted March 23, 2012 Report Share Posted March 23, 2012 see everyone keeps saying that there are three different tables. i don't think so..i plotted the sea data all together (1980-2006) and i actually got a decent sine graph out of it. Reply Link to post Share on other sites More sharing options...
chrnomyuu Posted March 23, 2012 Report Share Posted March 23, 2012 @Ckbrady1. No, some people will be using different fuctions, or different constants for their fuctions. it's found analytically so we'll all have different equations.2.not necessarily3. don't use the years. use "years since 1980" so 1980 would be 0, 1981 would be 1 and so on 4. depends on what parent function you are using. i used a sin function, so i found my constants by analyzing the plots for max, min, amplitude and period5. wish i had the option of choosing a different task >_<6.we can't really tell you our equations because we won't get the same thing. not to mention you need to be able to show how you got your equations from their parent functions, you won't be able to do that if we just gave it to you.@ibsurvivorif i remember correctly you'd place the functions in a bracket and state their domain restrictions.@helenaokay, start by plotting the data. i didn't use multiple functions for my data, so you don't have to I got a decent sine graph to fit. Once you plot your data you are supposed to discuss the parameters, so basically what x and y are in the data, and also restrictions (here's an obvious one but one you should have in there: x and y values cannot be negative. it's supposed to be a real life situation, and you cannot have negative years or negative tonnes of fish). comment on trends, and discuss suitable models: what type of function would best fit this data? you won't find something exact, just analyze the trends and you should be able to pick out some sort of functions to use. once you think you have a parent function that works you are just going to algebraically figure out it's constants.a sine function is going to be f(x)=asin(b(x-c))+da is the amplitudeb is the periodc is the phase shiftd is the middle then plot it on the data, and adjust the constants if necessary to get a better fit. you don't have to use a sine graph by the way, i just did.then for the fish farms data you graph the model you just found against the data (and it shouldn't fit at all), then use the regression feature on your calculator to find a model for this data. plot both models together and discuss trends. 2 Reply Link to post Share on other sites More sharing options...
Radu Stancu Posted March 26, 2012 Report Share Posted March 26, 2012 Does anyone know how to plot a polynomial function of 6th order on the GDC TI_84? Reply Link to post Share on other sites More sharing options...
venice Posted April 7, 2012 Report Share Posted April 7, 2012 i got this recently and i don't know how to generate functions for the first and the last table...please help!! Reply Link to post Share on other sites More sharing options...
Queens&Lionheart Posted July 24, 2012 Report Share Posted July 24, 2012 you're welcome if you face any problem then just post here!Hi, I am having difficulty identifying the appropriate models for the fish farm and I would really appreciate any help. Shall I create a different model for each table to make two different exponentials or can i combine the first two tables to create one exponential, and then make a third degree polynomial for the last table? Is my approach with the exponentials even valid?Thanks, Mike Reply Link to post Share on other sites More sharing options...
Maiki Posted August 21, 2012 Report Share Posted August 21, 2012 Hello, I am really stuck with this IA. How do you find what the formula is for the graph of the first part? Please please help Reply Link to post Share on other sites More sharing options...
rmalgo Posted August 21, 2012 Report Share Posted August 21, 2012 (edited) I'd just like to clarify with someone (anyone) what "Analytically" means in this task's context. I understand that it concerns itself with the fact that "Technology" should not be used in any way for that part of the task, but, specifically, does that mean no usage of the GDC whatsoever? Even if it meant testing out the functions I have come up with?Algebraically, this part should be possible to do, but I'm not entirely sure how that's to be done. It seems that some have done it that way already (I read through the WHOLE thread until the end), but I don't think we actually covered this in our Math SL class (or it is possible that I just didn't get the lesson, hence it did not stay in my head too long for memory recall). What I do know how to do is this guesswork "technique" where I guess the individual values of each variable.If it is feasible for anyone here to do, what chapter heading might help me in this Portfolio Task? If it might help, the textbook we're using is IBID Press's 2004 edition of Mathematics Higher Level (Core)I would greatly appreciate any answers to my queries, even if it were just this last question. Edited August 21, 2012 by rmalgo Reply Link to post Share on other sites More sharing options...
shriya2413 Posted October 5, 2012 Report Share Posted October 5, 2012 guys i know this is gonna sound really stupid but im kinda new at this so plz bear with me. so when i use polynomial degree 3 the eq is ax^3+bx^2+cx+d=0, i take random values of x and i get coefficients of a,b and c but how do i get d and since the value of y is say 244, how can i equate the equation to zero n then where will i put the value of y?thanks in advance! Reply Link to post Share on other sites More sharing options...
xscoolkids Posted October 11, 2012 Report Share Posted October 11, 2012 Hey everyone! We were assigned this IA for this semester. I would like to ask if any would know how to do this IA? I tried starting but it seems that i'm not going anywhere. It's due this coming Monday, by the way... Reply Link to post Share on other sites More sharing options...
kara14 Posted October 15, 2012 Report Share Posted October 15, 2012 Would anyone like to explain what the parameters or contraints are? I have a terrible math teacher that literally just handed this to us, said good luck and gave us 5 days to do it... Reply Link to post Share on other sites More sharing options...
ib252 Posted October 17, 2012 Report Share Posted October 17, 2012 (edited) hey, so guys I just wanna ask. Did any of you graph the data points first into your GDC then solved to find the SinReg etc?cause that's what I did..... but then i'm quite confused on how to model my own graph.oh, and which graphing softwares would you recommend because I think there are some which can automatically find the function for you? Dunno what they are though...oh btw are you guys pretty sure these are all tangent/sin cause some people I know got different stuff (for the sea data) so now i'm confusedthanks --oh and btw if any of the questions I asked have alrdy been answered above, please just ignore them and sorry Edited October 18, 2012 by ib252 Reply Link to post Share on other sites More sharing options...
Helena123 Posted October 30, 2012 Report Share Posted October 30, 2012 Hey all,I really need help! I think that the last part (from 1997-2006) can be modelled with a polynomial function..but that requires that I find a degree for the equation!How do I find the polynomial degree of the Data points??? Reply Link to post Share on other sites More sharing options...
13oss Posted November 9, 2012 Report Share Posted November 9, 2012 what is the equation for the first part of this portfolio Reply Link to post Share on other sites More sharing options...
adupat Posted November 25, 2012 Report Share Posted November 25, 2012 I have one question for the 2nd set of data. Many ppl have said that to find the constants of "a", "b", "c", and "d" in the eqn. y=A*sin(Bx+C)+D, we need to substitute the value of x and y in the equation to find it. But how does this work? we will need 4 eqns since there are 4 constants to be found. I tried doing so on mathematica but it just doesnt work. Is there any way that i can calculate the unknowns. Any help will be deeply appreciated Reply Link to post Share on other sites More sharing options...
stuckinib3 Posted November 29, 2012 Report Share Posted November 29, 2012 Hey guys, I just started my IA and it is due tomorro. (Procrastination at its finest)Anyway, I am so stuck on this. How are you guys getting the neccessary regressions? By doing a piece wise function and doing different graphs, or sticking them all on one graph and finding the regressions there?Please help me!! I am stuck Reply Link to post Share on other sites More sharing options...
adupat Posted December 3, 2012 Report Share Posted December 3, 2012 Hey guys, I just started my IA and it is due tomorro. (Procrastination at its finest)Anyway, I am so stuck on this. How are you guys getting the neccessary regressions? By doing a piece wise function and doing different graphs, or sticking them all on one graph and finding the regressions there?Please help me!! I am stuck Use piece wise functions they work out better. I dont think one function will be able to graph all the data points accurately. Reply Link to post Share on other sites More sharing options...
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