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mathcalculus
Group Title
HELP MATRICES:
If a= [4,3, 2; 0, 5,2] (2x3 dimension matrix)
c= [ 7,1; 2,7] (2x2 dimension matrix)
then 5AA^t+6c =
 one year ago
 one year ago
mathcalculus Group Title
HELP MATRICES: If a= [4,3, 2; 0, 5,2] (2x3 dimension matrix) c= [ 7,1; 2,7] (2x2 dimension matrix) then 5AA^t+6c =
 one year ago
 one year ago

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blurbendy Group TitleBest ResponseYou've already chosen the best response.0
I'm assuming A is referring to a? If so, the first thing I would do is take the transpose of matrix a, since you have A^t in your equation. Are you familiar with how to do that?
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
Yes, i transposed A^t= dw:1374263685200:dw
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
Looks good, so now I would multiply this matrix by the original a matrix.
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
the problem i have is knowing which number to multiply with which and also last at c
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
A good rule of thumb is to multiply scalars at the end. The scalars in this case are 5 and 6
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
i did this: 5(4) (4)+6c 5(3)(3)+6c 5(2) (2)+6c 5(0)(0)+6c 5(5)(5)+6c 5(2)(2)+6c and also, how do i know what dimension the new matrix will look like if a is a 2x3 dimensions and c is a 2x2 dimension? doesn't that say not allowed to be multiplied? unless the middle numbers are the same?
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
Hold on, you have to actually multiply matrix a by a^t, so you'd have: dw:1374264066231:dw this is a 2 x 3 matrix * 3 x 2 matrix, which will give you a 2 x 2 matrix. Then you would multiply each value in your 2 x 2 matrix by 5
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
i swapped the negatives on the 2's. sorry about that
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
oh okay. so basically I multiply.. row and columns?
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
Sort of. Matrix multiplication works like this: dw:1374264402007:dw
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
do you understand what you have to do?
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
To calculate the position next to 29 in the new matrix, you would multiply the first row in a by the SECOND column in a^t
 one year ago

mathcalculus Group TitleBest ResponseYou've already chosen the best response.0
after? not really
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
you need the next position in the matrix (next to 29), so to calculate the position next to 29 in the new matrix, you would multiply the first row in a by the SECOND column in a^t
 one year ago

blurbendy Group TitleBest ResponseYou've already chosen the best response.0
Just do what you did to get 29, exception this time multiply the first row by the second column
 one year ago
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