I'm happy with my TI-89. That's all I have to say about it.

Amen!

I would have voted if there was something in between "I don't like my calculator" and "I buy every calculator TI makes"

Well, I've seen a lot of discussion for just about every TI calculator except the old TI-92 (noting the reference to a 92 with a Plus module). I have been using my good ole 92 with no problems, so I see no reason to spend (read: waste) money on any new calculators or upgrades to this model. Also considering all of the appearant problems when it comes to assembly on the 89/92+, I doubt I would ever want to leave the nice, warm, fuzzy feeling you get with Fargo II programming on a TI-92.

Ahhh.... So relaxing... :o)

YESSSSSSs
AMEN Brother Aaron!

now if we can find a third person on this site who agrees we MIGHT constitute a small minority and gain some political sway...

-Anubis

Damn, i hate having to admit this...
I don't really know how to solve multiple equations on my 89 (I never needed it yet, and I have quite a past about discovering this on my calc on exam days, honest story!), so anybody with some pointers on it...

Cd_Slayer

It's easy. Say you have two equations:

x+5=y
y/x = 15

Using the solve (Under the Algebra Menu on your calc) function do the following:

solve(x+y=5,x)
ANSWER: x = 5-y

solve(y/(5-y)=15,y)
ANSWER: y = 75/16

solve(x+(75/16)=5,x)
ANSWER: x = 5/16

You just keep plugging the variables back into one another. This is why math teachers don't always like the 89, because of it's algrebraic manipulation. But, students usually are okay with it. (Of course.)

Dark Ninja

"No computer is secure unless it is turned off, unplugged, locked in a steel safe, and buried 50 miles underground, and is guarded by highly trained, highly paid armed guards with Dobermen as pets. And even then, I wouldn't bet my life on it."

You just seperate the equations with an " AND "
so it would be something like:
Solve(x+5=y AND y/x = 15,{x,y})

that is all.

Actually, I've noticed that that method often takes huge amounts time on quadratics and higher degrees...

if the eq is :x+5=y
then won't be x+y=5

for this kind of eq, you can read the manual and use a little big command called "simult"
x+5=y
y/x = 15

supose you have your eqs:
x+y=5
y/x=15 ----> y=15x ----->15x-y=0

15x-y=0 ----> [15,-1][0]
x+y=5 ------> [1,1][5]
simult([15,-1;1,1],[0;5])
answer:[[5/16][75/16]]
(pretty printed, obviously, like matrix)

(type equation 1, catalog>and (hit enter) type equation 2 ,{x,y})

Does that work for 3 variable systems?

Yes and it works for systems with even more variables.

someone said above that this way is slow. I prefer to use "simult"

But still, what's faster?
Solving 26 variable systems on an 89, or
solving 26 variable systems on paper?

Solving a 26 variable system using simult on the 89 is faster than using "and"(Talking about calc speed). There's a cute basic program that allows you to enter all the eq of your system and then the program solves it using simult(I think). Obviously is better to use "and" when eq are awful, since for the use of simult you need to arrange all the eqs.

Using a matrix with rref( is pretty quick too. I'm not sure how many variables you can use with it though.

I would go and get a new TI if it was better than what I have now unless TI goes and
screws me again like last time. The day after I go and buy my TI-86 TI announces
The release of the 89. DOH!

Same thing happend to me, I got a ti-92 and the plus module, and a month later found out they just realesed them together as a whole packege. If i had whaited one month i would have saved some money.

i have a ti-83+. it was the preferred calculator for my ap stat class. it's also the newest one my teacher knows how to use. she also uses it for ap calc. i would like to get a ti89, especially since the stat app was released. but i wont have any money untill i start working for the summer. i may need one for next year too: is anybody majoring in computer science/engineering and using a ti89? is it worth buying it?

Yes, it is. I got one for my birthday, (I had an 82 before) and it blows everthing else away. It's like switching from a 286 to a Pentium III (Which i also did, BTW) My friend liked it so much he sold his 83 and a tazer to his brother to buy one. The most useful feature is its algebraic manipulation. It can do problems that would take you 5-10 minutes. (We're doing equations way out to the 5th degree, and it saves me 95% of the time) I suggest you sell your 83+, since you probably won't need it. Then you'll have a bit more cash. But it's more than worth it.

Unless your like me and like to hoard calculators. I've got over 20 different calculators, 18 of which I never use.

I'm the same! I've got about 20 use and I only use my graphing calcs (85, 81, 83+ and FX7400 G Plus

Sadly, I lost my TI-36X Solar. Borrowed to someone at school. They lost it. It was a good calculator. We were the best of friends. Way better than my 89, always blaring out that rock music.
It could add, and subtract, and multiply, and divide, and even could do trig functions. Now I'd like to see my 89 do that. :)

Future Engenner here, and if you wanna finish it, you'll need it. Maily if your more concerned about programming than math...

Can't say anything about the 89. I use an 86 at work and at school. As a budding machinist and engineer I do some far out things on it. (Fractions and geometry. heh heh) The thing is really good. I've dropped it from twenty feet up, gotten down, reassembled it from the bits and pieces, and pressed on and continued to use it. It's also really good at resisting sparks when I accidentally leave it on top of the lathe.