TI-84: Systems of Equations (2- or 3-variable) Solving Program

[@yashsachdev5040]

OMG! I just wrote the program as you suggested and damn, it's so amazing. Thank you, Alex. This video deserves a lot of likes and views🙌🏻 Much much appreciated!!!👏

[@colins3989]

I actually love this man! Thank you so much!

[@mariasheils4470]

Thanks for the wonderful program, very crafty. On the TI 84 plus: APPS>#9 (PlySmlt2)>#2 (simult eqn solver) and choose the number of equations and unknowns to create a matrix>GRAPH>enter the variables A, B, C,....>graph . Problem solved without additional programming!

[@curtaincommander]

Thanks for pointing this out! I've had several students over the years point out that TI started building these types of apps right into the calculators... oh well! Glad you enjoyed the video!

[@monak4854]

❤❤❤❤

[@OMaMaRMY]

I really appreciate this! thank you

[@mariahg2988]

Very helpful thank you so much . !!!!! 100%

[@andreameigs1261]

You don't need to write a program to do this. You just use the apps 8, then 5, simultaneous equtn solver, if you are doing what I think you are doing. You can do multiple equations and multiple variables. THere is also an app that solves the quadratic equation for you, which I didn't know, so I wrote a program to do that as well. THey also have constants for both physics and chemistry... fabulous.

[@curtaincommander]

That's nice to know! Thanks for sharing! I have several students who still use a TI83 or TI84 with previous operating systems that don't have those apps, but it's nice to know the fine folks at Texas Instruments have built this into their more recent machines!

[@huongtu7238]

Thank you!

[@williamvandergrift9741]

Holy crap thank you so much!!

[@jaazielolayinka6865]

WOW thank you!!!

[@Jack-uc6nm]

Thank you

[@gemma3960]

thank you so much!

[@YA-xq3nj]

Hey thank you so much for the video! Except it doesn’t work for negative numbers, as in I can’t put a negative value in place of abcd

[@curtaincommander]

It should work just fine for negatives! Just be sure you're using the "negative" sign (next to the decimal point) instead of the "subtraction" sign.

[@YA-xq3nj]

@@curtaincommander Ah yes that makes so much sense😅thank you😭

[@michaelburnham3202]

For the 3 variable, do I need to have my D_1, D_2, D_3, all equal zero? or will that just output zero?

[@curtaincommander]

When you run the program, you do need to pay attention to what those coefficients are. So if you have a 3-variable system, each equation will have an x, y, z as well as a constant. It is possible that zeros can show up in the equations themselves, so it's simply a matter of making sure everything is organized properly (i.e. x term + y term + z term = constant) before entering. You don't need to force the constant to be a zero each time. I hope this helps clarify!

[@gabriellemueller8848]

Hello, I'm new to math. Can you tell me, please, what are the A2, B2, C3 ? Are they in place of the varable?

[@curtaincommander]

Those values represent where you would type in the coefficients (the numbers in front of the x, y, z, and the number on the right of the equal sign). A1 means the number in front of x in your first equation, B1 refers to the number in front of y in your first equation, and so on. Hope this helps!

[@siblingsquad8255]

Do u have to input all this in every time I you use the program

[@curtaincommander]

You don't need to write the program each time, but there are a lot of numbers to enter each time you run the program. Like anything, it becomes easier with practice, and it's incredibly helpful to have a quick check for problems like these, especially for the 3-variable systems!

[@michelle20900]

This is great. Thanks. What will the output of the program give on the calculator screen if it is a 'no solution' or 'many solutions' answer?

[@curtaincommander]

This is a great question! Since those special cases are unable to produce an inverse matrix, you would likely see an error like "SINGULAR MATRIX" to indicate the special case. I'm sure it's also possible to program in some simple checks in the form of if...else... statements early in the program to look for those special cases before running the actual matrix work.

[@bigkyraslatslat6809]

This does not work.

[@curtaincommander]

I've used it for a few years without any issues, so I think the code is correct. What error is it giving you?

[@bigkyraslatslat6809]

@@curtaincommander it says “error:argument”

[@curtaincommander]

@@bigkyraslatslat6809 You may just want to check what's entered in the rref(. There may be a missing or misplaced bracket [ or ] in there. If that's the cause, it should be a pretty easy fix!

[@edwinma3864]

OR you can just show how to use matrices and not waste so much time writing this program

[@curtaincommander]

You're totally right; matrices make short work of systems, though they typically aren't taught until higher levels of high school math. My intention here was simply to provide students who haven't learned matrices in their classes with a means of checking their work when they first learn the substitution or elimination methods in their early algebra classes.