Inverse of a 2x2 matrix | Matrices | Precalculus | Khan Academy

Example of calculating the inverse of a 2x2 matrix

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[danielchickering]

He explains it better in two minutes than math teachers do in an hour

[Dafefoe]

Lord Bless you!!!! My teacher made this so much more complicated than it needed to be. WOOT!!

[firebird]

It may be useful to mention here that the determinate must NOT be equal to 0 in order for a 2x2 matrix to be invertible. This is because in the formula used to find the inverse of a 2x2 matrix, you must compute 1/determinate, and a denominator cannot be equal to 0, therefore the inverse cannot be found.

So in short, if the determinate = 0, the matrix does not have an inverse.

[airi]

I have a test on matrices tomorrow so I'm binge watching all the videos about matrices on your channel lol- these explanations are really straight forward and even though I sit in class for 45 mins hearing a teacher explain this, I don't understand anything. but watching this video makes everything so much clearer

[starqian]

But what's the point of this i don't get why we need to learn it

[angel.]

You're enthusiastic voice is me in any social situation.

[justincren]

I came here after trying to learn from online school and learned the info much better.
Thank you, thank you thank you!

[mikeduck]

But my in school they teach us that when u switch the first diagonals and take the negative of the second diagonal that’s the inverse of “A” instead of adj of “A” ... am confused 🤔

[assancamara]

This teacher knows how to explain with good examples. It is extremely important to consider an example that will leave no ambiguities. It was important for the 7 to be negative.

[alanwalter]

I know it's been years but still thank you a lot for sharing this. I am in ninth and doing self study for the upcoming board exams and your videos are helping me a lot. Hope I get good Marks.

[alanperez]

Thanks a ton Sal! This is a much easier process than my professor makes it to get this result! Hopefully she won't disqualify this procedure when I use it on my exam tomorrow!

[disasterXstrikes]

THANK YOU SO MUCH!!!!
~Sincerely, a Linear Algebra student.

[SniperzInvictus]

This guy deserves a raise. He has saved me numerous times

[TheWinnieston]

Thanks so much!

But why oh why would I need the inverse of a matrix and why is it so hard to get?

[AlbertoGonzalez-qzkw]

Thank you. My online class made this much more confusing that it had to be. You made my day.

[DharejaAcademy]

Good approach and colorful way guided well. But I think you must mention general formula how to get adjoint of 2-by-2 matrix for viewers. How ever good job.

[tylerdavis]

My teacher did another method and I think this is easier to find the inverse

[syedsadiqhussainshah]

Thank you, thank you, thank you, thank you, thank you, this is why whenever I am stuck I open Khan acedmy... Thank you again you made it so easy for me.

[sefakolichaba]

The explanation its more than the way lectures can do

[crazytoker]

you LITERALLY explained it better in 2 min than my teacher in 4 sessions -_-