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Type II - Fish Production


Noxen

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From the question, it stated 'plot the data points from the table on a graph. so i would suggest only one graph...I'm not conformed yet, though.you can use Excel or Geogebra...I still don't know what suitable models should I use that have similar trends...I wish someone colud help me on this...

well at the very first, you present the tables and plot everything on one same graph. but then to generate the formula, you combine a number of functions.

I was thinking of using sin(x)/x. but i could not figure out how can i combine the functions together? any ideas?

okay so you want to use sinx/x for the whole thing or only for one section, then another function for another section, yet another function for some other section, or how?

if you want to use 1 function for the whole thing, well that's it. no need to combine anything.

but if you want to use several functions, you can present it with:

gif.latex?y=\begin{Bmatrix} function 1 \

but without the closing bracket }

Hi. :)

I just wanted to ask, the data that you are referring to, is it the data from the total mass of fish caught in the sea or is this data from the fish farms? sorry, im kinda confused :/

thanks.

the first three tables on the top, in the beginning of the task.

Edited by Desy Glau
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  • 3 weeks later...

ohh CUBIC. okay you should've told me that :P

in the mean time can you refer to this first? http://www.ibsurvival.com/index.php?app=forums&module=forums&section=findpost&pid=99521 I know it's for a different IA, but it's actually the same, just with different data. for cubic, it's just one less variable, with similar working as in that post.

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ohh CUBIC. okay you should've told me that :P

in the mean time can you refer to this first? http://www.ibsurviva...dpost&pid=99521 I know it's for a different IA, but it's actually the same, just with different data. for cubic, it's just one less variable, with similar working as in that post.

Than you Desy...i think that i will figure out how to find a,b,c and d....now do you have hints how to find values for sine function?...:)

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you're welcome :) if you face any problem then just post here! hmmm sin is easier, right? you could guess from the period, amplitude, etc :)

ok, i know how to find a,b and d...but how do I find c?? is c constant? ://// because if i write like this (y-d)/a-sin(b*x)=sin C. it is different for different values of

x and y.....:/

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d is the vertical translation whereas c is the horizontal translation. like, for d, how far away is the midpoint (point right in the middle of the max and min points) from 0? for c, how far is the start of the graph from 0?

I do not get it....:((( these formulas for a and d, are they correct?

if I write that c= b*x - sin^-1((y-d)/a) is c constant? :/

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Yakuza, use your GDC or if you want you can try Geogebra or Autograph (google it)

brigadirsa, I don't get what you're saying at all. the formula is y=a sin(bx+c) +d where a,b,c,d are constants. so you should get numbers.

ok desy, i get it...they are all constants...and i figured out how to find values of a,b and d analytically...but how do i find value for c without using technology...that is my problem...

can you give me formula for calculating c from this function? :/

Yakuza...

for the period between 1980 and 1988 i used cubic function...use TI or some computer program to plot the data and use cubReg to find a,b,c and d or look at previous posts from Desy if you need to find these values analytically.

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