E-CodeLinear system, exact answers — a TI-89 Titanium program
LINSYS89 is a TI-89 BASIC program for the TI-89 Titanium. Solves 2 to 4 linear equations by Gauss-Jordan in exact arithmetic, so the answers stay fractions like 1/3; reports no solution or infinitely many (with the rank).
What it asks for and what it shows
It asks for 4 values at its prompts. In the example below it shows X1, X2, X3.
Example run
One of its oracle test cases: “3x3 integers”. The inputs are typed in order, and the results are the values the case expects on the screen.
| Step | Value |
|---|---|
| You enter | |
| Input 1 | 3 |
| Input 2 | {2,1,-1,8} |
| Input 3 | {-3,-1,2,-11} |
| Input 4 | {-2,1,2,-3} |
| The screen shows | |
X1= | 2 |
X2= | 3 |
X3= | -1 |
How it's checked
7 test cases, each checked against an independent method. Replayed key by key on a virtual TI-89 Titanium, they make 40 checks.
How E-Code checks every program
Run it or put it on your calculator
- Open the library in the TI-89 Titanium calculator and pick “Linear system, exact answers” (LINSYS89).
- Put it on your own calculator with a computer and a USB cable, or type it in by hand.
Related programs
- Cramer's rule with every determinant
- LU decomposition with pivoting (exact)
- Linear system Ax = b from a typed matrix
- Matrix inverse, exact
- Matrix inverse from a typed matrix
All TI-89 Titanium math programs · All TI-89 Titanium programs