CALCULATOR GUIDE
Depending on your model of calculator, you may be able to solve systems as large as 10x10 with ease using a simultaneous solver. I have included the directions for a TI-86 below. If you have a TI-84 or TI-89, please refer to my Calculator Guide to Echelon Form (RREF) instead.
Solving a System of Linear Equations using SIMULT:
| To solve a linear system using SIMULT | Example 1. Solve 3x+5y=33, 4x-3y=15 Answer. x=6, y=3 |
| TI-86 ONLY Press 2ND SIMULT to enter your simultaneous systems solver. It will ask you "Number" meaning how many equations (or variables ... they should be the same). Type in the number and hit ENTER. The next few screens ask for the coefficients of the variables. You must have the equations in order: x, y, z, etc., equals sign, constant number. Enter the coefficients from the first equation pressing the down arrow between each entry and between each equation. When you are finished, press the SOLVE on the screen. The answers are given in the order you entered them, x, y, z, etc. If you want to review or change your inputs, press COEFFS. |
2ND SIMULT It asks "Number=" type 2 ENTER Now fill-in the coefficients as shown below. a1,1 = 3 a2,1 = 4 SOLVE
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coeff of x in eq 1This is going to be a real time saver!
Example 2. Solve the following system on your calculator.
a - 2b - c + 3d = 12
2a + b - d - 3c = -5
-2a + 3b + 2c + d = -13
2b + c - 2d = -8Note:
- In the second equation be sure to rearrange the terms so they are in an order consistent with the other equations -> 2a + b - 3c - d = -5
- In the fourth equation there you will need to use a zero as a place holder where the a-term is missing -> 0a + 2b + c - 2d = -8So the numbers entered into SIMULT in order of the four equations will be:
first 1 -2 -1 3 12
second 2 1 -3 -1 -5
third -2 3 2 1 -13
fourth 0 2 1 -2 -8The solution is a=3, b=-4, c=2, d=1. Did you get it? Now try solving this system algebraically instead and you will come to really appreciate your calculator!
Originally written: 2000-05-08
Last revision:
2007-09-19 05:50 PM
