matrcies and determinants

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[umbral vessel]

What is the determinant of an upper-triangular matrix?

[steady lichen]

the diagonal

BUT like i get it the ans is a^3

but why did they give matrice=0

is that irrelevant

[umbral vessel]

No

What do you know about a?

Given that ALL the coefficients in A are equal to zero

[steady lichen]

so a,b=0?

[umbral vessel]

Yes

Conclusion?

[steady lichen]

then determinant of a is 0???

[umbral vessel]

Not of a

a is a number

[steady lichen]

A i mean

[umbral vessel]

Yes

That's it

[steady lichen]

so none of these?

OH OKAY tysmmm

[umbral vessel]

Also, you technically don't need to know that a = 0, A is not invertible

[steady lichen]

so?

[umbral vessel]

A square matrix has a determinant of zero if and only if it is not invertible

The zero matrix is not invertible

[steady lichen]

ohhh

yea its not

okay damn thats a new trick tysm

[umbral vessel]

👍