So, one of the problems has me doing a bunch of matrix multiplication using these:
A = [-1 0 2] B = [-1 0] C = [-2 1]
[ 3 1 4] [ 4 2] [ 1 3]
The one in particular that I'm stuck on is A(B+C):
B+C is easy enough but multiplying a 2x2 by a 2x3 isn't possible but, in the answers my teacher turned it into a 3x2:
[-1 3]
[ 0 1]
[ 2 4]
Clearly in the problem A is stated as a 2x3 so how did he make it into a 3x2? Any tips and help is much appreciated!
A = [-1 0 2] B = [-1 0] C = [-2 1]
[ 3 1 4] [ 4 2] [ 1 3]
The one in particular that I'm stuck on is A(B+C):
B+C is easy enough but multiplying a 2x2 by a 2x3 isn't possible but, in the answers my teacher turned it into a 3x2:
[-1 3]
[ 0 1]
[ 2 4]
Clearly in the problem A is stated as a 2x3 so how did he make it into a 3x2? Any tips and help is much appreciated!
-
There is a typo in your question, a 2x2 can multiply with a 2x3, but A(B+C) would be 2x3 by 2x2...
Which isn't possible
What your teacher did is transpose the matrix, it basically swaps the ith row to the jth column..
This shouldn't be written as A(B+C) since A is given to be a 2x3 matrix, what should be written is A^(T) (B+C) , read as A transpose mulitplied with B+C
If this is a applications problem and you can't determine why the matrix is being transposed then I suggest doing a search for forums and such that already asked the question, like this:
http://www.physicsforums.com/showthread....
or this:
http://www.katjaas.nl/transpose/transpos...
et cetera
Which isn't possible
What your teacher did is transpose the matrix, it basically swaps the ith row to the jth column..
This shouldn't be written as A(B+C) since A is given to be a 2x3 matrix, what should be written is A^(T) (B+C) , read as A transpose mulitplied with B+C
If this is a applications problem and you can't determine why the matrix is being transposed then I suggest doing a search for forums and such that already asked the question, like this:
http://www.physicsforums.com/showthread....
or this:
http://www.katjaas.nl/transpose/transpos...
et cetera