Is there anyway to use a TI-89 to find the determinant of a matrix that includes variables? For example, say you want to find the determinant of the following 2x2 matrix:

[[1-x,0][1,2-x]]

Obviously, this example is probably quicker to do by hand, but on our final exam we will likely have to find the determinant for 3x3 or 4x4 matrices and I would like to have an easy way to check my answer.

Thanks for the help!

4/29/2010 12:32:03 AM

the same way you find it normally?

4/29/2010 12:44:14 AM

Don't have an 89 on me right now but... I thought there were was function in the matrix or math menu det(

4/29/2010 7:33:42 AM

^ Yah, but for some reason that function doesn't work if you include variables (it pops up some kind of notation error).

It works perfectly fine though if the matrix is [[1,0][1,2]].

4/29/2010 9:27:05 AM

http://education.ti.com/downloads/guidebooks/graphing/89ti/TI89TitaniumGuidebook_Part2_EN.pdf

example in the manual uses symbols, maybe titanium is different? i'd check, but i'm not sure where mine is

4/29/2010 9:55:39 AM

^^ I'm pretty sure there's a way, but I can't remember it at the moment. I used to do it all the time in Controls/Vibrations and have variables outputted.

[Edited on April 29, 2010 at 2:02 PM. Reason : -]

4/29/2010 2:01:49 PM

Did you try det([1-x,0;1,2-x],x) ? the ,x should resolve the error message...

[Edited on April 29, 2010 at 3:05 PM. Reason : ..]

4/29/2010 3:01:41 PM

i have old 89 and titanium they same as far as functions. my fav thing on Titanium is it gives you onscreen clues about how to arrange your comments for your functions. time to throw that crap away and use Maple tho dude. but to answer your question, if i remember correctly you not suppose to have a little algebraic expression in your matrix, i don't think Ti-89 set up for that, you got to do it as a separate calculation and then save the result as a variable and put the name of that variable as a constant into your matrix. It's been too long tho, go to that Ti link that other guy gave you. Or better yet, learn the material. Nobody designs tests such that you actually benefit from Ti-89 anymore. Also there is probably a special application just for Matrices that will work way better than the original built in matrix functionality

4/29/2010 6:41:24 PM