Oxford Linear Algebra: Eigenvalues and Eigenvectors Explained

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  • เผยแพร่เมื่อ 1 ต.ค. 2024
  • University of Oxford mathematician Dr Tom Crawford explains how to calculate the eigenvalues and eigenvectors of a matrix, with 2 fully worked examples.
    Check out ProPrep with a 30-day free trial to see how it can help you to improve your performance in STEM-based subjects: www.proprep.uk...
    Test your understanding with some practice exercises courtesy of ProPrep. You can download the workbooks and solutions for free here: www.proprep.uk...
    You can also find several video lectures from ProPrep explaining the topic further here: www.proprep.uk...
    And fully worked video solutions from ProPrep instructors are here: www.proprep.uk...
    Watch other videos from the Oxford Linear Algebra series at the links below.
    Solving Systems of Linear Equations using Elementary Row Operations (ERO’s): • Oxford Linear Algebra:...
    Calculating the inverse of 2x2, 3x3 and 4x4 matrices: • Oxford Linear Algebra:...
    What is the Determinant Function: • Oxford Linear Algebra:...
    The Easiest Method to Calculate Determinants: • Oxford Linear Algebra:...
    The video begins by introducing the eigenvalue equation which we are trying to solve, with a discussion of possible methods of solution. We see that the only way a non-zero eigenvector can be found is if the determinant of the characteristic matrix is zero, which gives us the characteristic equation, or characteristic polynomial. Solving this equal to zero gives the eigenvalues, which are then substituted back into the eigenvalue equation to give the corresponding eigenvectors.
    The method is demonstrated first with a 2x2 matrix example, and then for a 3x3 matrix. In both cases we consider a general eigenvector before choosing one parameter to make the final vector as simple as possible.
    Produced by Dr Tom Crawford at the University of Oxford. Tom is an Early-Career Teaching and Outreach Fellow at St Edmund Hall: www.seh.ox.ac....
    For more maths content check out Tom's website tomrocksmaths....
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ความคิดเห็น • 57

  • @user-pp5lo5ky4i
    @user-pp5lo5ky4i 2 ปีที่แล้ว +94

    Here we go eigen.

  • @cll2598
    @cll2598 6 หลายเดือนก่อน +8

    The only video on TH-cam that explains both concepts in an intuitive way without compromising on the mathematical details

  • @TomRocksMaths
    @TomRocksMaths  2 ปีที่แล้ว +5

    Check out ProPrep with a 30-day free trial to see how it can help you to improve your performance in STEM-based subjects: www.proprep.uk/info/TOM-Crawford

  • @juliussoldan4016
    @juliussoldan4016 2 ปีที่แล้ว +24

    Just wrote my Linear Algebra 2 exam yesterday at UWaterloo. Admittedly, I had more of a love and hate relationship with these 2 courses, but near the end and looking back at them, I did really enjoy them. Seeing these videos and actually being able to understand what's going on just makes me realize how far I've come, and if I could go back in time I would definitely take them again.

  • @RC32Smiths01
    @RC32Smiths01 2 ปีที่แล้ว +13

    Always look forward to this quality information. Math with a fun and humble twist to it

  • @Abhisar_Gupta
    @Abhisar_Gupta 7 หลายเดือนก่อน +5

    What a fantastic explanation. Thanks a lot.

  • @jvdroid9074
    @jvdroid9074 ปีที่แล้ว +6

    Man, that was the kind of video I was looking for, it was so good to watch. Thanks for you job!

  • @manfredvonrichtofen3863
    @manfredvonrichtofen3863 8 หลายเดือนก่อน +4

    I am finally at a point at which I can use your videos as guide, not just as interesting videos about Math I dont understand :D

  • @lovisatroedsson5056
    @lovisatroedsson5056 ปีที่แล้ว +3

    Your voice is so nice to listen to…

  • @rogeriojunior9459
    @rogeriojunior9459 2 ปีที่แล้ว +2

    i wish i had learned it like that, but instead, the first time i saw it, was just proving hard theorems about existence of eigenvalues and eigenvectors, or orthonormal basis of eigenvectors or something like that, never had the time to actually play with the characteristic polynomial and find actual eigenvalues, great video

  • @owen7185
    @owen7185 2 ปีที่แล้ว +4

    Seriously it's great having someone who can teach math

  • @pedrolironderobles3012
    @pedrolironderobles3012 2 ปีที่แล้ว +4

    As always, great explanations and very interesting content!!

  • @koioioioi
    @koioioioi ปีที่แล้ว +2

    Although im still only in secondary school watching this is very interesting, so i will continue :D

  • @rasainsbury
    @rasainsbury หลายเดือนก่อน

    In the 3×3 example, the eigenvector associated with eigenvalue -1 should be (1, 3, -3)'

  • @F89_
    @F89_ 9 หลายเดือนก่อน

    ok there's one thing I'm slightly confused by. Where does the 6-landa come from? in my head that became 5 landa instead of 6 (I know this video came out one year ago but I'll shoot my shot.) I know this is a very simple thing to understand but I still don't really get it so yeah if anyone sees this and can explain it, it would be greatly appreciated 🙏

  • @pepemosquera6005
    @pepemosquera6005 2 ปีที่แล้ว +2

    Great lecture! saw you at the duocon and decided to take a look to your channel, and this video was exactly what I needed for my algebra course, hoping to see diagonalization soon

  • @ACC861
    @ACC861 2 ปีที่แล้ว +4

    Would also be good to hear the geometrical notions of Eigen values and eigen vectors!!

    • @TomRocksMaths
      @TomRocksMaths  2 ปีที่แล้ว +8

      But 3blue1brown is so much better for that!

    • @ACC861
      @ACC861 2 ปีที่แล้ว +3

      @@TomRocksMaths Aha!! Love the shoutout to Grant!! I was hoping to get your thoughts on geometrical notions of EV's!! But regardless in recent times, I definitely watch 3Blue1Brown along with your videos to get a complete overview of the topics!! Recently, I have started watching Dr.Steve Brunton's (Associate Professor, University of Washington) channel too!! Afterall, the more insights that I get... the more I appreciate the lore behind the math!!

  • @davidmurphy563
    @davidmurphy563 ปีที่แล้ว

    Ok, the linear algebra is fine but the factorisation is basically witchcraft. I'll ask my son to teach me.

  • @mnqobimsizi4328
    @mnqobimsizi4328 4 หลายเดือนก่อน

    I WILL BE USING THIS METHOD TILL I DIE, IT EASY THAN DOING THE GAUSSIAN ELIMINATION

  • @unruly_ronin
    @unruly_ronin 3 หลายเดือนก่อน

    This video has been the closest I've ever come to understanding this thing

  • @kiemanh1332
    @kiemanh1332 10 หลายเดือนก่อน

    at 8:38, i thought it supposed to be landa-5 at the first entry?

  • @johnchristian5027
    @johnchristian5027 2 ปีที่แล้ว +2

    Nice video, I love linear algebra!

  • @chanceneck8072
    @chanceneck8072 2 ปีที่แล้ว +1

    Own values? 😅🤔🤷‍♂️

  • @tamasburik9971
    @tamasburik9971 2 ปีที่แล้ว +1

    Wish I could've had you as my linear algebra prof

  • @DistortedV12
    @DistortedV12 6 หลายเดือนก่อน

    Does he talk about spectral values? SvD?

  • @owen7185
    @owen7185 2 ปีที่แล้ว +1

    Awesome Tom. I'll join Proprep as linear algebra I have this semester 👍👍

  • @umehmoses8118
    @umehmoses8118 ปีที่แล้ว +1

    Love you Doctor, wish to meet you someday

  • @fabiangn8022
    @fabiangn8022 2 ปีที่แล้ว +2

    gracias.😉👍🏾

  • @kanyamagaraabdallah8300
    @kanyamagaraabdallah8300 ปีที่แล้ว +1

    merci frere je va retour sur ce video a bintot!

  • @arthursteenkist2595
    @arthursteenkist2595 2 ปีที่แล้ว +2

    Great lecture! 🙏🏻

  • @ihaveacreeplingdepression5708
    @ihaveacreeplingdepression5708 ปีที่แล้ว

    you are soooo goooooodd

  • @darcash1738
    @darcash1738 9 หลายเดือนก่อน

    I was practicing elementary row ops for the 3x3 example, so I did r3 + r2/lambda. You end up getting an extraneous soln of 0. Btw how do you work backwards to get the A matrix from a given Eigenvalue and Eigenvector? Eg, lambda = 2, and (1, 0, 0) like the example. Or are these vectors sort of just for some characteristic of the matrix that is useful to us?

  • @RTD553
    @RTD553 11 หลายเดือนก่อน

    Brilliant. But couldn't we just argue that the determinant of a transformation matrix represents the scale factor applied to the modulus of a vector? So if we want a result of zero when applied to a non-zero vector, we need a determinant of zero?

  • @juliusteo
    @juliusteo 2 ปีที่แล้ว +1

    10:28 Why is the general vector a 2×1 and can it be a 2×n?

    • @TomRocksMaths
      @TomRocksMaths  2 ปีที่แล้ว +2

      It would be n x 1 in the general case of a n x m matrix.

  • @rameshpanta8062
    @rameshpanta8062 ปีที่แล้ว

    Great intuitive explanation at the beginning. I was waiting for intuitive examples on its applications. Thank you !

  • @unknown-fm5bm
    @unknown-fm5bm ปีที่แล้ว

    I have a question. z in every case to be any value ?

  • @souravchakraborty6766
    @souravchakraborty6766 ปีที่แล้ว +1

    🙌🙌🙌🙌

  • @nityambohare719
    @nityambohare719 2 ปีที่แล้ว

    I am waiting since ages of linear algebra's good lecture and my patience pay off thank you sir

  • @ummerfarooq5383
    @ummerfarooq5383 2 ปีที่แล้ว

    That 30 second explanation.

  • @guuguu7559
    @guuguu7559 2 ปีที่แล้ว

    a cool maths teacher doesnt exis- 😳

  • @tomasbruna3004
    @tomasbruna3004 8 หลายเดือนก่อน

    Man, this is amazing.

  • @sidsiva3073
    @sidsiva3073 2 ปีที่แล้ว

    You had written z=4z then went on to write z=0 . How ?

    • @TomRocksMaths
      @TomRocksMaths  2 ปีที่แล้ว +4

      If you subtract z from both sides you get 3z=0 and so z=0

  • @owen7185
    @owen7185 2 ปีที่แล้ว

    Would you state at the beginning that vector v is not zero? In an assessment situation?

    • @rogerlie4176
      @rogerlie4176 2 ปีที่แล้ว +3

      An eigenvector is by definition nonzero.

    • @owen7185
      @owen7185 2 ปีที่แล้ว

      @@rogerlie4176 thank you

  • @InAMinMaths
    @InAMinMaths 2 ปีที่แล้ว

    9:10 there’s a shortcut here where you can just put, where lambda = m, m^2 - (sum diagonal)m + detA which instantly gives the characteristic equation. I’m this case sum diagonal = 6, detA = 8. 10:06 better to complete the square.

  • @donegal79
    @donegal79 2 ปีที่แล้ว +1

    unfortunately, this simply goes through the simple mechanics of determining values - zero explanation, insight, into what these represent. Frankly, could have gotten a smart 14 year old to do this video. You need to up your game mate, stop appealing to middle of the road engineering students.