Finding Eigenvalues on TI 84 Calculators

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This is a new presentation format I'm experimenting with so let me know if you like it. This video demonstrates how you can find eigenvalues and graph a characteristic polynomial using the TI-84 calculator without writing an actual program. Enjoy!

Опубликовано:

12 сен 2024

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Комментарии : 48

@ZephKin 6 лет назад

Wow... thank you dude. My prof's been writing (X-lambda(ID))=0 NOT (lambda(ID)-X)=0 for 2 lectures now. Now it makes sense!

@CorySiebler 10 лет назад

Awesome! Works fast even if the guess is way off. I need to find the largest eigenvalue for Katz centrality and this is extremely helpful!

@DanZc_22 4 года назад

Even though I am still having some issues with my calculator when plotting the curve (idk why it tells me 'wrong dimensions), this video is just amazing. Bro, for real, the help has been tremendous, thanks a lot for sharing this video, just what I needed for my final tomorrow.

@jeremylanemathstats 4 года назад

You are welcome. I am curious about the error you are receiving. You are not the first to mention this type of error. Can you walk me through your exact steps? I'd like to try to duplicate this issue and hopefully resolve it. Thanks.

@starman_217 5 лет назад

Tremendously helpful! I know it's been ages since anyone commented, but this just made my exam-taking life that much easier. Thanks!!

@jeremylanemathstats 5 лет назад

Glad it was helpful, good luck on your exams.

@elizango2363 10 лет назад

Thank you so much. Doing this is mush easier.

@moradmoradi8518 4 года назад

Extremely Helpful, thanks Mr. Lane,

@jeremylanemathstats Год назад

Glad it was helpful!

@RedChallenger4 10 лет назад

Sounds great, is there a way we can find the eigen values without having prior knowledge of what the eigen values actually were?

@RedChallenger4 10 лет назад

If not, is there a way we can make an efficient guess?

@jeremylanemathstats 10 лет назад

If you plot the characteristic polynomial by having det(XI - A) in Y1 slot, you can make good guesses as to the real eigenvalues.

@teddyweaver5197 Год назад

What is the software you used to present this? Very helpful!

@jeremylanemathstats Год назад

It is a TI-Emulator software from Texas Instruments website. I believe the place to start is here: education.ti.com/en/downloads/trial-software but be aware that TI uses 3rd parties to sell emulator software, so you may not get the same one shown here. I tried to get an updated version by contacting their customer service and they sent me a different version, so now my TI-videos are not the same. Hope this helps. Thanks.

@zachrichard9440 4 года назад

Can you do another one for TI-84 Plus CE? The syntax is much different on that.

@jeremylanemathstats 4 года назад

Not at this time since I do not have access to a TI-84 Plus CE. Sorry.

@zachrichard9440 4 года назад

@@jeremylanemathstats no problem, thanks anyway

@mrngkahwee95 7 лет назад

Is there a fast way to guess for value of x? I guess we do from 0,1,2,.... till we find the nth eigenvalue? Thanks :)

@jeremylanemathstats 7 лет назад

Using the graph of the characteristic polynomial you can use the zero option under Calc. If you are using the Solver option under Math you would only get one eigenvalue at a time. Without a program like QR factorization (usually with Givens Transforms) you would not be able to get all eigenvalues to output at once. I hope this helps. Thanks.

@bludgeon1081 2 года назад

@@jeremylanemathstats So, to find the other eignevalues, would you need to just keep inputting guesses?

@jeremylanemathstats 2 года назад

@@bludgeon1081 It depends, plotting the characteristic polynomial and using the zero command may speed up the process and prevent random guessing. Also, there are plenty of theorems concerning eigenvalues that may help in localizing them. Gershgorin's Theorem is one such theorem.

@bludgeon1081 2 года назад

@@jeremylanemathstats Interesting, never heard of it. Thanks for still replying to comments!

@bludgeon1081 2 года назад

@@jeremylanemathstats One last question, is it possible to also find what the characteristic polynomial is on this calculator? I know you can do it with TI-86 but not sure if it works on this one.

@rysoucie2 9 лет назад

Thank you so much!!

@gmacsports89 9 лет назад

How did you find out what to guess? I did a few other matrices and missed out on an eigenvalue because I did not guess enough or close enough.

@jeremylanemathstats 9 лет назад

The best way is to plot the characteristic polynomial to obtain some good initial guesses. The ones that were demonstrated here were from textbooks or very small and easy to approximate. So under Y1, you can do det(X * identity(n) - A) and the calculator will plot the characteristic polynomial. You can trace for an initial guess or use the zero command to find them directly. It's up to you. Good luck and thanks for watching the video.

@gmacsports89 9 лет назад

Jeremy Lane Thank you very much! Great instructed video.

@samanthasmith145 5 лет назад

This video is great and very helpful! I have a TI-84 Plus CE and I am trying to solve for my eigenvalues using this method but I keep getting an error of "Error: Data Type", stating I have a wrong value/variable type entered by attempting to store a matrix to a list. Have you encountered this before? It is frustrating and I do not know how to solve for matrix A in the calculator if I cannot enter it. Do you have any recommendations? Thanks!

@jeremylanemathstats 5 лет назад

Have you tried using the matrix directly? I am confused by your attempt to store the matrix as a list.

@samanthasmith145 5 лет назад

@@jeremylanemathstats I did use the matrix directly. I followed the directions as in the video and I am getting that error for some reason. I am not sure what is wrong, maybe the solver function has changed some in the newer calculator models. I downloaded your program from ticalc.org and that is working for me, so I will use that instead. Thanks for the quick response and your help! It is a nice program and I appreciate your work!

@teddyweaver5197 Год назад

@@samanthasmith145 You may not be using alpha solve

@corytinz 4 года назад

so why was the second guess value for 'X' 5, would that same guess work in every scenario?

@jeremylanemathstats 4 года назад

That was chosen due to the matrix, remember we solved for the eigenvalues by hand first and 5 was close to the eigenvalue 5.37... Because the Solver command uses a variant of Newton's method for solving, a guess of 5 will not always be acceptable for every matrix. Examine Gershgoren's theorem. This may help you in providing a guess for real eigenvalues. Thanks for watching.

@RedChallenger4 10 лет назад

Also, sorry for throwing questions. Does this work with complex values?

@jeremylanemathstats 10 лет назад

Unfortunately, no. The solver command is confined to finding real solutions only.

@user-nf4ee5qu4o Год назад

Does this work on TI-83 too?

@jeremylanemathstats Год назад

I believe it should. There are no special commands used exclusively by the TI84 to do this. The commands should also be available on the TI83. Give it a try.

@menyouh771 6 лет назад

Thanks for the tutorial! How do you find eigenvectors for a matrix with the help of this calculator? Would appreciate the help!

@jeremylanemathstats 6 лет назад

I do not know of a way to determine eigenvectors on this calculator without a program. There are several programs for eigenvalues and eigenvectors at ticalc.org though.

@menyouh771 6 лет назад

Thanks a lot!

@ti84org 2 года назад

Search for 4*4 matrix eigenvalues ti84 and you will find a ti-basic program that automatically calcuates the eigenvalues without guess.

@masonmills8140 3 года назад

LETS GOOOOOOOOOO

@masonmills8140 3 года назад

You really came in clutch on this one; saved my ass for sure. Or at least a few hours of work. Thanks b

@jeremylanemathstats Год назад

Glad I could help.

@mbenitez6722 4 года назад

This is some serious bs -_- you did a great job man but honestly it’s a lot of work to even memorize the steps, like the calculator can do RREF in a simple command but not Eigenvalues and vectors 😒

@Nboost8 4 года назад

It's not that bad. Once you set up your "Solver" all you have to do is edit matrix "A" to be whatever inputs you need. When you go back to "Solver" it will automatically pull from your matrix "A". The guessing sometimes is a pain, but oh well.