I want to know how to solve a matrix with complex numbers in a TI-84 plus calculator!

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.

Try entering on the same command line your calculation followed by the ToFrac command. That should work. Here is a screen capture from a TI83Plus in complex mode (a+ib).

Here is screen capture of a similar calculation, performed on TI Nspire with TI 84 plus keyboard.To type in the imaginary unit use key sequence [2nd][dot], do not use [ALPHA][X^2] for the letter i.

Be sure to use the (-) negative key and not the - minus key.

One program for doing this is at
http://www.ticalc.org/archives/files/fileinfo/250/25081.html

Well, the equation is Ax=b and we want so solve for x
There are several ways of entering the data, but this is one way
Code: A=[15+35i 29+1i; 46+13i 62+3i]
b=[0;0]
x=A\b which has the trivial solution x=[0;0] (the ";" means "next row", a space next column.) To input a matrix use APPs then Data/Matrix Editor then New. Then change Data to Matrix. Put in the name such as "AA" in the variable field. Then enter row and column dimensions. Then edit as a spread sheet. Use F6(util) to delete a column or row. To manipulate matrices, exit the matrix application, then go to MATH then Matrix. Notice that J(RowOpps) is available. Good luck and thank you for using FixYa! We would sure appreciate a 4 "thumbs-up" rating for this answer. Happy holidays!

The >FRAC command only works for real numbers. For complex numbers you have to convert the two components separately.

Hello,
The matrix Math tools, are accessed by pressing [2nd][MATRIX] ->>[MATH]. Scroll the list to find all row permutations, etc.
Sorry but you will have to implement your Gauss-Jordan method yourself, and interactively.
Hope it helps.

Hello,
To solve Ohm's law you need no sophisticated calculator. If you know two quantities, you readily calculate the third. Application of Kirchhoff's (two h) laws to linear circuits, gives you a linear system of equations. If a calculator can solve linear systems, or handles matrices, the limitations would pertain to the maximum dimension of the matrices.
I just tried the TI83 to define a 45x45 square matrix and a 55x45 matrix. The maximum number of rows or columns is 99. But it will depend on memory.
If you have the TI84PLUS Silver Edition it should be fine. You can upgrade to a TI 89 Platinum, which can handle symbolic calculations (with undefined coefficients a, b, c).
Hope it helps.

Press MODE and select one of the two complex modes.