Find Determinant Formula

harpazo

harpazo

Full Member
Joined
Jan 31, 2013
Messages
891
Find a determinant formula given

\begin{pmatrix} w & x \\
y & z
\end{pmatrix}

Let me see.

w times z minus yx

Answer: wz - yx

Can I also switch y and x?

Answer: wz - xy
 
As xy = yx (for any real numbers, anyway) then of course you can. It doesn't simplify anything that I can think of though.

Bear in mind you can find a determinant of this matrix where w, x, y, and z are matrices or something more exotic. In these cases the xy replacement won't work.

-Dan
 
topsquark said:
As xy = yx (for any real numbers, anyway) then of course you can. It doesn't simplify anything that I can think of though.

Bear in mind you can find a determinant of this matrix where w, x, y, and z are matrices or something more exotic. In these cases the xy replacement won't work.

-Dan
Click to expand...

I found this question online.
 
Otis said:
The forum guidelines do ask for that info, but it would be better to provide it in the op.

Regarding y·x versus x·y, look up Commutative Property of Multiplication.

Pro Tip: Addition is also commutative.

?
Click to expand...

Ok. I will continue to work on this.
 
I assume that the OP knows that the commutative law of multiplication works for real number so I am a bit concerned about this question. Do you know that the elents in the matrix are real numbers or do you think they are something else? Seriously, you must know what type of objects you are working with!
 
Jomo said:
I assume that the OP knows that the commutative law of multiplication works for real number so I am a bit concerned about this question. Do you know that the elents in the matrix are real numbers or do you think they are something else? Seriously, you must know what type of objects you are working with!
Click to expand...

Jomo,

Read my latest post in the Math Odds and Ends forum entitled Hello Math Friends: Bad News. Go read what I said and hopefully I will be back soon to continue my review of math learned long ago. Right now, I am simply overwhelmed with anxiety and extremely worried. I am facing a personal crisis.

harpazo
 
Yes, I read it but you are still posting. I hope all works out!
 
Jomo said:
Yes, I read it but you are still posting. I hope all works out!
Click to expand...

I have not posted in terms of math. I do check in every now and then but nothing related to math. I do miss Sullivan. I'll fix this mess.
 
harpazo said:
I found this question online.
Click to expand...
I would expect the source to make clear that symbols w,x,y,z represent Real constants (unless you found the question somewhere like facebook or yahoo).

;)
 
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