<p>Hello, I'm a 2nd year undergrad college and math major.</p>
<p>All my life I've used Casio, which is fine as a scientific calculator, but using a Casio graphing calculator has put me at such a disadvantage in all my math life because everyone, teachers and all, use Texas Instrument. Back then I was just too lazy/stubborn to learn TI (also didn't wanna pay more $$). But as I go into upper division courses and have my professors continually use TI to demonstrate how to do this and that, I really want to finallyy make the switch...I don't know how to use my Casio graphing calc for sh** aha...</p>
<p>Anyway, I'm deciding between TI-84 and TI-89. I know that TI-84 is sufficient enough and people also say that learning how to use a TI-89 is too complicated, so they would rather stick to 83 or 84 because those suffice. I'm just wondering since I'm completely new to the TI series, whether it's worth it to spend the extra $$ on TI-89 because I'm basically learning from scratch how to use either one. Which model should I get?</p>
<p>I’d just stick with the 84 honestly. I have both and honestly have never used my 89 because I don’t know how to do squat with it. It really doesn’t make much sense- the 84 is very intuitive, at least IMO. Granted, I’m just in linear, so we’ll see how much I use the 89 in the future.</p>
<p>@DrGoogle it will vary (and also depends if you buy used or new). Assuming I want shiny new ones, on Amazon I see TI-84 go for as low as $90 new and TI-89 for $120 new, so like $30 difference.</p>
<p>Also @guineagirl96 can I ask what can you do with the 84? I’m still on the boat for getting a whole new graphing calculator because like I said, I do own a Casio graphing calculator, it’s just that teachers and all always use TI so I can’t follow in class demonstrations.</p>
<p>Here is just a short list of what can/can’t do on my current casio GC:
take definite integrals
take derivatives at specified points (you have to input a point and it’ll give you a value, won’t give you the general equation)
find determinants/do operations with matrices
solve linear systems, just up to 3 unknowns
x can NOT take indefinite integrals or general derivatives
x can NOT solve differential equations</p>
<p>I assume 84 can do at least all of this, but does it do more (like take indefinite integrals, or give you derivative equations? what about solving differential equations?)</p>
<p>The TI-89 has a “computer algebra system,” which means it can solve equations in terms of variables, factor equations, etc.</p>
<p>Personally, I prefer the TI-89, and I think it would be worth the $30 difference. Also, learning to use it is moderately easy (but not as easy as the TI-Nspire).</p>
I used both the 89 and the 84, with the 84 being solely for statistics while the TI-89 is good for everything else. After I learned to use R, the 84 became quite useless.
TI-89 takes a bit of time to learn but once you learn it, it’s an amazingly useful tool.