# Matrix/Linear Algebra Quickie...

#### 5Ws

##### Banned
Matrix/Linear Algebra Quickie...

If A is nxn, det(-A) = det(A) only when n is even right?
and if n is odd, det(-A) = -det(A) right?
Kind of a crucial step for a proof I had to do on today's test.

#### AeroJonesy

##### Diabloii.Net Member
Yeah, I'm pretty sure you're right, but not 100%. It's been awhile since I went over those rules.

edit: In my head it makes sense, since when you are taking the determinant of an even matrix, you are always taking products of even amounts of numbers (4 things getting multiplied in a 4x4, etc) so the negative signs will cancel out.

#### 5Ws

##### Banned
OK, found the thing in the book:
A-nxn
det(kA)=k to the nth power times det(A).
Therefore in our case, k=-1, so yeah, I think I got it right, whoohoooo!

#### SuggestiveName

##### Diabloii.Net Member
5Ws said:
OK, found the thing in the book:
A-nxn
det(kA)=k to the nth power times det(A).
Therefore in our case, k=-1, so yeah, I think I got it right, whoohoooo!
Yes, without double checking my book I'm like 96% sure you are correct. God I long for the days of linear algebra.... *goes back to pondering 3-manifolds* Mmmm...topology in 4 dimensions, yummy.

#### Isolde212

##### Banned
Here we go with the sexy math talk again...

#### SuggestiveName

##### Diabloii.Net Member
Isolde212 said:
Here we go with the sexy math talk again...
No more mocking math majors or so help me god I will rigorously prove that canada does not exist. Then you dissapear in a puff of logic.

#### Isolde212

##### Banned
SuggestiveName said:
No more mocking math majors or so help me god I will rigorously prove that canada does not exist. Then you dissapear in a puff of logic.
I wasn't mocking. I honestly think math geeks are sexy. It's wierd. I think my obsession developed when I went to university and most of the guys there were either engineering or math students. For once someone was talking about something I just couldn't understand. I find it fascinating.

#### SuggestiveName

##### Diabloii.Net Member
Isolde212 said:
I wasn't mocking. I honestly think math geeks are sexy. It's wierd. I think my obsession developed when I went to university and most of the guys there were either engineering or math students. For once someone was talking about something I just couldn't understand. I find it fascinating.
It never fails...all the girls that dig math geeks are always taken.

#### AeroJonesy

##### Diabloii.Net Member
SuggestiveName said:
It never fails...all the girls that dig math geeks are always taken.
I hear you on that one.

#### 5Ws

##### Banned
SuggestiveName said:
No more mocking math majors or so help me god I will rigorously prove that canada does not exist. Then you dissapear in a puff of logic.
OMGZ, a lapdance-less OTF??? I cannot imagine!