Math - Determinant

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#1

In this lecture we look at how to find the determinant of a matrix, which is an essential step in finding the matrix inverse. It can also tell us whether a matrix can be inverted in the first place.

We used the laplace expansion to find the determinant because it’s one of the more universally applicable options that is easy to visualize.
However, there are a lot of other options out there, including some neat shorthand tricks for when you’re working with matrices of specific sizes.

Do you know any interesting ways to find the determinant of a particular n x n matrix? Why not share your favorite method below!

#2

I think there is a mistake in the form for the Laplace calculation. In the videos it’s been said that it starts with:

- + - +

But in the example calculation it’s been calculated like:
+(-3) - (-12) + (-9) => -3 + 12 - 9 = 0

#3

@Pharraz, thank you for raising this question.

The pattern applies between each number and tells you how to combine them.
So the first is always unchanged (since it’s the first number), then we subtract the second, add the third, and so on.

Apologies if my explanation of this was unclear in the video.
Hopefully this makes sense now, but if you have any other questions please do let me know.

#4

Thanks for pointing it out.

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