Inverse Matrices | MIT 18.06SC Linear Algebra, Fall 2011

Inverse Matrices
Instructor: Ana Rita Pires
View the complete course: ocw.mit.edu/18-06SCF11
License: Creative Commons BY-NC-SA
More information at ocw.mit.edu/terms
More courses at ocw.mit.edu

[@georgesadler7830]

Professor Ana Rita Pires, thank you for an awesome video/lecture on Inverse Matrices in Linear Algebra. This is an error free video/lecture on KZbin.

[@-steady-8215]

Shouldn't have used computationally heavy problems for demonstration. Concept is important.

[@tiagotassinari1435]

Thank you very much for the lecture!!

[@ninhonto7946]

she could have done R2-R1 then R3-R2 at the beginning of the elimination, saves her one step :P And she did give me a heart attack at 5:38... :')

[@mberoakoko24]

+Michael Xu infact i got confused at that stage for a while then saw that we ended up with the same solution

[@malekmawaheb6285]

c'est fabuleux

[@yalaforge]

Got it, thank you :)

[@YashavendraSingh]

You are great

[@chaoticoli09]

I took a different, faster, and easier approach. I personally computed the determinant of A, solved det(A) = 0, and then those values of a and b which satisfy that equation (a=/=0 and a=/=b) are the conditions on a and b such that A is invertible. Maybe this comes as a later theorem, but it's not very hard to prove that A is invertible if and only if det(A) =/= 0.

[@SilverArro]

Oliver Hohman Agreed, but at this point in the course, determinants haven’t been introduced yet which is why she took this approach instead.

[@NoActuallyGo-KCUF-Yourself]

That's what I did too. I just found the inverse and looked at it. Then confirmed by computing det(A). I suppose if I just looked at the original matrix and thought about it, I could reach the same conclusions, but if I want to know if it's invertible, then might as well just invert it and see what happens.

[@skmangalkumar851]

Very good

[@nanakokuroi3619]

That's what she said...

[@lawrencedovin688]

I like this girl, she's pretty awkward =))

[@LordMgls]

logo apanhada no Gram Schmidt!!!

[@emadrawashdeh4226]

What is the different between lecture and recitation? and where i can find the videos of lectures?

[@mitocw]

Recitations are used to cover anything that was confusing in the lecture. To see the complete materials in context, see the course on MIT OpenCourseWare at: ocw.mit.edu/18-06SCF11. The course contains lectures, recitations, lecture notes, assignments with solutions, and exams with solutions. Best wishes on your studies!

[@pexma]

7:23 :s howwwwww?

[@MrJeanlouiszhong]

You need to end up with [1,0,0] as the row1, but you have a [1,b/a,b/a] here which means you must subtract [0,b/a,b/a] from row1. A combination of row2 and row3 gives you a [0,1,1], then multiply it with b/a, now you have the [0,b/a,b/a] you are looking for.

[@1222233maggotx]

Portuguesa, claro!!!!!

[@lucasm4299]

1222233maggotx In an American University!! Yes! 🇺🇸🏆

[@ae0072]

WHy use such a difficult method? There are easier ways to do it..

[@PlushChronicles]

Oh god no lol

[@rounakstanley]

Lol she's kinda cute tbh

[@rounakstanley]

Oh and great video! Helped a lot