How do i use my ti 84 plus to solve problems with the gauss jordan method, to obtain the cofactors of a matrix, and many oder operations with matrices

Does this help?

How to Solve System of Equations on the TI 84 Plus

Good luck,

Paul

Shift [x^-1] allows you to access the matrix features. Under Names you select the names you want to use for your matrices. Under Math you access the various commands. Under Edit you edit the contents of your matrices.

The TI-84 allows only real numbers in a matrix.

You can write programs to deal with complex numbers in lists, simulating matrices. One such program is at http://www.ticalc.org/archives/files/fileinfo/250/25081.html

Hi Robert9004x2,

If you want to examine the matrix you want to inverse and, the one that is given you trouble pressing [2nd] [MATRX]. Then stroll and, select the one you want to look at by pressing, [ENTER]. You'll have to press, [ENTER] again and, matrix should display at the Home screen. At the Home when you get to them your looking for the ones that are not square, like 2 by2 or 4 by 4 etc. You might need to re-edit this matrix so, that it is square.

Your trying to invert a matrix that isn't square you might be using using the proper key sequence to create a inverse matrix. Here what the correct inverse matrix look on the Ti 84 Plus Home screen.

And pictured below is a Matrix is being inverted by using the ^ and the -1 keys. Which to inverse a Matrix on the Ti 84 Plus you have to use the [x^-1] key.

This is not the proper way to inverse a Matrix on the Ti 84 Plus. The proper way to inverse of a matrix, the [x-1] key must be used, instead of pressing the sequence [^][-][1]. The [x-1] key is the official inverse key and is located right under the Math key. It is also the same key that you use to get to the matrix menus. The [^][-][1] sequence is only raising the matrix to the -1 power and, will cause an error too. If you need any more help, just post a comment and, I'll respond quickly.

Hi biancaaii,

You need to re-install the Ti 84 Plus OS, ASAP!!! You can fix the problem by installing the newest Ti 84 Plus 2.55v. MP OS. operating system.

If you have a friend that has a Ti 84 Plus or, Ti 84 Plus Silver Edition you can connect the two calculators together through the IO link ports and, they can send you a copy of their OS while you receive it on your Ti 84 Plus. Hopefully your friend will have Ti84 Plus 2.55v. MP OS on their calculator or, it might not work.

If you can't find a calculator to connect to you can connect your Ti 84 Plus to a computer that has Ti Connect software on it. If you need to connect your Ti 84 Plus to a computer make sure the Ti Connect software is operating properly. You do not want any hang-ups while installing the Ti 84 Plus OS. Be careful, even a power failure during the process of installing the OS will destory your calculator.

Procedure 1 to installing the latest Ti84 Plus 2.55v. MP OS

1). You can get the latest copy of Ti84 Plus 2.55v. MP OS and, guidebook by going to the Texas Instruments web site. You can get to that site instantly by clicking, "Ti 84 Plus 2.55v. MP OS!" Once your at the Ti site click the Download Item, "Ti84 Plus family operating system". Next you can login or, click "continue as guest". I'd would click the "continue as guest". Once you have click, "continue as guest" the Ti84 Plus family operating system will download to you.

Next, click "SAVE" and then a window to a folder will pop up. It is probably a window to a folder that you download too. If so, you may want to change it and, save to this folder, "My Documents \ My TI Data \ Downloads". You can also go back and, download the Ti 84 Plus guidebook too, if needed.

Link your computer and, Ti 84 Plus calculator with the USB cable or, Direct Black Link cable that came with the Ti 84 Plus calculator. Next, drag the Ti 84 Plus 2.55v MP OS that you saved earlier in "My Documents \ My TI Data \ Downloads" out of that folder and, drop it in the "Ti Connect" icon on the desktop. Click, "Continue" when the "Erase Warning" pops up and, the new Ti 84 Plus 2.55v MP OS will begin to install.

Next, the Ti Device window should pop up and, highlight the port when it finds what your Ti 84 Plus is using, USB1 cable or, Direct Black COM1.


When the Ti Device Explorer finds and, highlights your calculator's information click, "Select." Then click, "Yes" when the next window shows up with your calculator's information and, the OS will continue to download. Upon completion the newest Ti 84 Plus 2.55v. MP OS will be installed.

If you run into any trouble with software or, drivers just comment to what failed at this posting and, I'll be glad to help you.

A singular matrix has no inverse. It's the equivalent of zero: trying to take the inverse of zero is an error. Check the matrix to make sure you have entered it correctly. If the error persists, could you post the matrix in question?

Press 2ND [MATRIX] to bring up the matrix menu. Select the matrix whose inverse you want. Press x^-1 to invert it. x^-1 is on the same key as [MATRIX], the second key down from the ALPHA key on the leftmost column of the keyboard.

There is no command on the calculator that allows you to do it.
You can use the calculator to evaluate the minors for each element (the determinant of the matrix that is left when you remove the column and the row that have that element as intersection).
Here is an example how to calculate the cofactor of the _11 element of a 3X3 matrix.

1. I defined a 3x3 matrix called b
2. I defined a submatrix by removing the first row and the first column of the b matrix.
   
3. The submatrix is called min11.
   
4. Its determinant is the minor of the _11 element of matrix b.
5. The cofactor cof11 of _11 element of matrix b is the product of (-1) to the the power (1+1) and the minor of the _11 element.
6. The cofactor is represented by the last result to the right of ->cof11, that means b22*b33-b23*b32.
7. For additional information refer to your algebra book.
   

the cofactor (C) of Matrix (A) = (det(a) times (A)^-1)t

Cof A=(detAxA^1)t

Enter a matrix for (MatA) AC
shift 4 7 gives det(_
shift 4 3 shows det(a )<-end Paren
= x shows ansx
shift 4 3 shows ansxMatA -1x
= you'll see a Matrix AC to get out
shift 4 8 gives Trn(
shift 4 6 shows Trn(MatAns) =


The Matrix graph shows all the Cofactors