Inverting 3x3 part 1: Calculating matrix of minors and cofactor matrix | Precalculus | Khan Academy

Beginning our quest to invert a 3x3 matrix. We calculate the matrix of minors and the cofactor matrix.

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[mbisetakobana]

best teacher in the world!you deserve a nobel prize man, your effort is just tremendous

[rod]

Maybe I'm weird but inverting a 3x3 matrix using this method is actually one of my preferred things in math so far ! :D Anyway, I can't thank you enough for these videos, helped me a lot.

[xxdogexx]

Bro you saved my life, my teacher told me to learn this on our own for a project, no intervention from her. You were the only way I was gonna pass this project many thanks!

[shira]

Thank you! My teacher didn’t explain it that good, and only now it’s clear

[TinyMaths]

Yes, the eternally long process of matrix manipulation by hand. I still haven't mastered it without making 'silly' little mistakes. But I never thought to map it out like you have done here. it's far less messy than the method I've been using. Glad I came across your vid on this one.

[allanbinoy]

Dude the way u just found out to find the co factor is just amazing bro! Hands off

[Neo-vcjr]

We have to find the adjugate (adjoint) of the co-factor matrix and then multiply it with the determinant of the parent matrix.

[TheDelaneyCurry]

Why is it that my textbook spends 20 pages rambling on and over-complicating the subject, in what takes you less than 10 minutes to explain! Even with the car alarm, this made more sense than my $200 textbook. Thank you!

[gugulethuzulu]

Thanx a lot I was really confused. Its my first time with matrices and I was completely lost.

[chasemarangu]

A visual learner, I skipped through most of the talking and checked the resulting diagram. Very concise!

[oududtygyfa]

very well explained. i recommend this video

[rudravaidya]

In the end you take the transpose of the matrix and then divide it with the determinant

[anoukfleur]

Not entirely clear: which determinant are you talking about in the end? The one of the cofactor-matrix, or the determinant of matrix C?

[vedsoni]

whats your most favorite thing to do by hand?

[yelbaut]

you need to transpose this co-factor first right before dividing it with the determinant

[jmoney-notk]

thanks so much lmao my teacher explained it weird this rly helps

[violettiourestinpeacetechn]

Not sure if anyone is going to answer this, but- What is a matrix of minors and what does it do? And what is a cofactor matrix? Thanks!

[gurumurthyd]

can u please tell which ur using for the board

[Onnethox]

Ahaha starting the vid real af. Even Khan Academy hates this bullsh*t but I dont understand when you have to put the number in front of the determinant matrix like: for the 1st number (-1) putting -1[1, 1, 4, 5] matrix. I dont know when or when not to do it.

[taureankartik]

on changing the columns the - + - sign changes right???