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## Question

In math today, my teacher showed us how to create a scatter plot of information, clicking some stuff to find a screen where it gives you the c, a, and r values fulfilling the equation y=c/(1+ae^(-rx)), and outputting random integers (unrelated, actually). So, cool, I know how to do all of this on a TI-84, but that's not really helping me too much. ;P

From my apps screen I've managed to find the Stats/List editor and input data, but I don't know how to graph it. Nor do I have any idea how to find the c, a, and r value screen. I can graph the logistic growth function no problem once I have them, though.

Oh, and for the random integers, on the 84 it's <number>->randInt(x,y), but I don't have randInt? (At least not under Math -> Probability.)

Any help is appreciated.

Hahaha. My homework is to find the point of maximum growth for Starbucks.

Edited by Izzy

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Unfortunately, my calculator is the TI-85 so not quite as advanced as yours, also, the last time I used it was about a decade ago. Luckily, the batteries are still going.

The only help I can offer, however, is that 'Catalog' shows you some of the functions of your calculator so what you need may be found in there. The manual may also be useful!

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In math today, my teacher showed us how to create a scatter plot of information, clicking some stuff to find a screen where it gives you the c, a, and r values fulfilling the equation y=c/(1+ae^(-rx)), and outputting random integers (unrelated, actually). So, cool, I know how to do all of this on a TI-84, but that's not really helping me too much. ;P

From my apps screen I've managed to find the Stats/List editor and input data, but I don't know how to graph it. Nor do I have any idea how to find the c, a, and r value screen. I can graph the logistic growth function no problem once I have them, though.

Oh, and for the random integers, on the 84 it's <number>->randInt(x,y), but I don't have randInt? (At least not under Math -> Probability.)

Any help is appreciated.

Hahaha. My homework is to find the point of maximum growth for Starbucks.

I have a TI-89 (but not the titanium edition), I don't have it with me right now but I'll try to say some of what I remember (haven't used it in at least 3-4 years )

Ok, I remember that when it comes to the graph screen you can only graph one and two variables. That's not gonna help.

But the stats/list editor can help you out here.... I "think" you don't graph the plot from the stat/list editor, but you rather add it to the graph's section of the calculator. Like I said, I don't remember the exact steps, but I do remember doing plots for my statistics class

About calculating the values of c, a and r; I don't know what exactly is the process for that... But for generating random integers there's a function called "Rand" (pretty sure), I remember seing it available for the programming part of the calculator. Look for it in the catalog or in the math section, try generating a random number from the home screen, I'm sure it's there somewhere.

If there's a given process for finding the c, a and r values and it's a pretty common task I'm quite sure it's available in the TI-89...

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Let us know if it worked

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Hey I found this, maybe it helps....

TI89man.pdf

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