Linear Algebra: Eigenvalues of a 3x3 matrix

[xxxNewEyesxxx]

I'm not dealing with interger soultions. :(

[KraussHelmut]

Sal, can you PLEASE make a multi variable calc playlist? And thank you so much for everything! I think it's hard to comprehend the help you are giving us all!

[ReferencesRStupid]

matrix addition is commutative

[ItsJoshNorman]

You totally couldn't find the lambda coefficients at 8:30 :P

[TerminatorSe7en]

Isn't it supposed to be det(A-lamda In) ??

[petecdun]

@TerminatorSe7en You can do it either way; given that you derive the equation from the definition of an eigenvalue, where A(v)=lambda(v), lambda(v) - A(v) = 0, but also, A(v) - lambda(v) = 0. So, you can use either det(A-lambda In), or det(lambda In - A), they're effectively the same thing.

[ChippyBlack]

yeah i also think its det(A-lambda), all my uni text books say that for finding eigenvalues and also later on when diagonlising matrices

[BrendanPanFlautist]

The roots are suppose to be both positive or negative right? But awesome video saved my ass on so many occassions lol. Wish me luck on my finals in two days =/

[ImAllDatRemains]

Great video, except that method you used to find the eigenvalues is disgusting should have just broke the determinate up. I did and it was much simpler and I find easier to follow.

[heezybrooge]

You saved my life

[honeypot11]

math is always hairy -.-

[guube15]

thnks for your helps it makes me feel good and iam happy now after i have watched this vedio . please make it more for benefit

[Crilleakaroffe]

p(lamdba) = lamdba^3 - 5lamdba^2 - 9lamdba + 27 = 0

Correction?

[ItsJoshNorman]

@Crilleakaroffe Unfortunately, an incorrect correction. Rewind the video to before he circles the coefficients and multiply it out; he has got it right but accidentally circled over the + sign to make it look like a - sign later on in the vid (when we all--in our heads-- go back and double check our calculations for errors like this)

[mylilcritic]

@Crilleakaroffe why is it -5lamda^2?

[jincontrol]

wont finding the determinant by cofactor be easier?

[Remerai]

Thanks a lot for this! I have a feeling this will help me a bunch!

[Decgaid06]

Big question, How to find Matrix A that you have there that represents L with respect to some bases S? I'm having problem with it...

[blrdawn]

not offfending u....u fool could hav done synthetic division aftr gettin cubic equation

[computingm]

THANK YOU VERY MUCH FROM KOSOVA !!!

[Strictz]

Absolutely brilliant, thank you so much.

[BullShitThat]

OMG I love you man

[UltimateTunage]

-3 lamda squared take away - 3 lamda squared is not zero :s

[matildakamberi]

i love you man come and seat near me in my exam

[pwnedbygary]

You can find the Eigen values alternatively by doing A-lambda*I. You can then only subtract lambda from the A matrix leaving the non-diagonal entries alone. One can them do the determinant calculation of the 3x3 matrix, doing cofactor expansion along any row or column to find the eigen values.

[halorulesyourface]

so.. much... writing... but still clearer than my prof. thanks man!

[narical]

i wish u did a video related to DIAGONALIZATION......

[MattMcq99]

if you do X-lambda you do not need to reverse the signs of the other values, correct?

[narissa999]

thanks so much, this was really helpful!

[ruhtraeel]

What happens if you have a remainder in your division?

[kasvroo]

nice tutorial

but does method of multiplication and subtraction to get the characteristic polynomial works with 4x4 matrix??

[kkbalaji08]

Thanks Very Easy TO Understand

[guzzbar]

when i do this 10 years from now? aha

final is 4 days, im gonna forget this in 5 :D!!

[jdnickell13]

@Cipher71..

[AlexThomson1000]

Thanks. It's actually all just number crunching if you understand the equation that difines eigenvalues.

[AlexThomson1000]

@AlexThomson1000 defines*

[MrSntna]

These videos are the only reason I pass uni maths. for the love of God keep doing them

[yoguely]

I've went through all your lineal algebra videos and learned a lot, but now in my university course, we are covering Hermitian, Skew hermitian matrixes, and unitary matrices. Help.

[alexandre10023]

Thank you ! really helpful.

[92blackrainbow]

amazing.

[fuxxooorlolz]

fuck this why do i have to have linear algebra in information technology... what a bs subject! anyway thanks a lot for the help T.T

[RQ0823]

try to use synthetic division rather that long division method...

thanks a lot man!

[giriisindahouse]

Thanks a lot, I always get trapped in this 3x3 matrix.

[MaruTheGreat]

I'm so glad this video is online, I'm currently taking a class on Quantum Mechanics (and I'm only 17), and the matrix algebra is incredibly complex, so this made it easier to understand...

[Unkn0wn500]

First of all, thank you for the great tutorial. Though, I prefer (A- lamda l) but offcourse both work. I suggest everyone to use horner's method to reduce the equation. Way faster and in my opinion easier ;).

[medo405]

Thank you, thank you and thank you...

Really, you are a hero, sir.

All my respect and god bless you!!!

[MsSpirite]

got my LA terminal exam tomorrow and i cant believe that i prepared it all in just 2 days thanx to your vids :p

[TheLover4you]

thank you , that was really clear to understand. Much better than my professor.

[0asdf0asdf]

at 9:00 it looks like its -4L^2 -L^2 = -3L^2 that confused me for ages!

[seebbix]

you helped me a great deal, thank you soo much

[schnitzerxx]

thanks

[rb44]

good tutorial...but isn't it supposed ot be (A - lamda I)?

[wolfezach1]

@rb44 it doesn't matter which

[kramaster3]

@rb44 I think (lamda I - A) is correct because i've seen it some of the other examples, but i guess it doesn't matter which way you put it :)

[tobsmonster2]

@kramaster3

Yea its actually correct either way as they're both derived from Ax=λIx, i.e

Ax=λIx

=> 0=λIx-Ax

=> 0=(λI-A)x

[cjrisi88]

@rb44 Both work!

[thebandcall]

@rb44

it doesnt make a difference

[ALBGunner04]

@rb44 It can be both.

[bmwilly131]

@rb44 it's the same thing...

if A = lambda I, obviously if you subtract the right side, A - lambda I = 0; and if you subtract the left side, lambda I - A = 0

[dhanu7005]

@rb44 its the same thing

[Pipfilosofen]

@rb44

it doesn't matter if it's the opposite way

[TheDutchPaul]

@rb44 multiply by a c=-1

[queenswatcher]

@rb44 if you times both sides by -1 then it will be. Either notation is right.

[baseballp730]

@rb44 yes it is... I was watching it and looking at my problem for comparison and was like wtf...

[fuckooo]

@rb44 both work

[sebastianblanco3]

@rb44 either way will work.

[x89codered89x]

@rb44 It shouldn't matter, because you could multiply the whole thing by -1 and still get the same eigenvalues.

[hanz12891]

@rb44 He already replied to that....it works both ways whethers its (A-lamda I) or (Lamda I - A)

[geotraker]

@rb44 you can see it the previous video (2x2 matrix) that the result is the same thing, but i've also lerned at university the way you said

[farestabs]

cool

[Cyanide1One]

Awesome tutorial! thanks alot!

[Cipher71]

You are my hero!

Also:

12:39

That's what she said!

[hifhif123]

lol...

do you know where the video for finding the eigenvectos are

[laputahayom]

@Cipher71

NOOOOOOOOO

[jdnickell13]

lol!

[kissmyass28]

Oh my god... you are always keeping up with my lectures all the time!! we just started this unit today!!!

[ace1dominant1]

good job

[vejito11]

Nice