TI-89 help please (differentiation/integration)

[#1procrastinator]

All I get is a matrix whenever I differentiate or integrate, it's always a 2x2 matrix with all 0s or an identity matrix

[Lasercookie]

That probably shouldn't be happening.

I haven't used a TI-89 before, but is it possible that your 'x' variable has been defined to something, which is screwing up the differentiation/integration.

Try clearing your variables or differentiating something that doesn't involve x, like 2t: .

Edit:  I don't know if you know how to clear variables, but looking it up, it uses the same syntax as the nspire:
delVar(x)

I'm thinking it's this x variable business because I had a friend have the same problem recently (but on the nspire).

[#1procrastinator]

Thanks a lot , I tried using a different variable and it worked

[#1procrastinator]

Hey do you happen to know how to the important information from a graph (i.e. x and y intercepts, turning points)? And when you 'trace' the graph, how do get it move in integers (right now, it goes up in 0.126582s)? Is it possible to mark the intervals? And when you're tracing and move to the edge, is there an option to make the screen shift to the new area?

[Lasercookie]

Hey do you happen to know how to the important information from a graph (i.e. x and y intercepts, turning points)? And when you 'trace' the graph, how do get it move in integers (right now, it goes up in 0.126582s)? Is it possible to mark the intervals? And when you're tracing and move to the edge, is there an option to make the screen shift to the new area?

I can't really help since I have an nspire, never used a TI-89 before.

If you google 'TI-89' + the thing you want to do, it normally gives back a lot of instruction guides like this:
http://people.richland.edu/james/ti82/roots/
http://faculty.chemeketa.edu/tmerzeni/mathcenter/math070/calculators/TI89/TI89graph.pdf

You might have some luck on youtube as well.

[ellecee]

Hey do you happen to know how to the important information from a graph (i.e. x and y intercepts, turning points)? And when you 'trace' the graph, how do get it move in integers (right now, it goes up in 0.126582s)? Is it possible to mark the intervals? And when you're tracing and move to the edge, is there an option to make the screen shift to the new area?

Go to the graph page (diamond F3) to see the graph.
Y intercepts: F5 Math, 1: Value, then type 0
X intercepts: F5 Math, 2: Zero, then cursor to the left of the intercept and press enter (lower bound) and cursor to the right for upper bound. This can be kind of annoying but you get used to it.
TP: F5 Math, 3 or 4 Min/Max depending on what type of TP it is. Follow the lower/upper bound instructions on screen.
Personally, I never use trace. It's much easier to go to F5 Math 1: Value and just type in the x values you want.

Basically, the Math menu is your best friend when it comes to dealing with graphs on the Ti-89. Hope that helped.

[#1procrastinator]

^Thank you! Haha I thought you said press diamond then F5 for the y-intercepts part and ended up in the table of values...cooool

@laseredd: yeah I did try searching before I asked but a lot of the stuff didn't really address what I was after (or at least not in a way I understood)