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mathcalculus
 2 years ago
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 =
mathcalculus
 2 years ago
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 =

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blurbendy
 2 years ago
Best ResponseYou've already chosen the best response.0I'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?

mathcalculus
 2 years ago
Best ResponseYou've already chosen the best response.0Yes, i transposed A^t= dw:1374263685200:dw

blurbendy
 2 years ago
Best ResponseYou've already chosen the best response.0Looks good, so now I would multiply this matrix by the original a matrix.

mathcalculus
 2 years ago
Best ResponseYou've already chosen the best response.0the problem i have is knowing which number to multiply with which and also last at c

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

mathcalculus
 2 years ago
Best ResponseYou've already chosen the best response.0i 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?

blurbendy
 2 years ago
Best ResponseYou've already chosen the best response.0Hold 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

blurbendy
 2 years ago
Best ResponseYou've already chosen the best response.0i swapped the negatives on the 2's. sorry about that

mathcalculus
 2 years ago
Best ResponseYou've already chosen the best response.0oh okay. so basically I multiply.. row and columns?

blurbendy
 2 years ago
Best ResponseYou've already chosen the best response.0Sort of. Matrix multiplication works like this: dw:1374264402007:dw

blurbendy
 2 years ago
Best ResponseYou've already chosen the best response.0do you understand what you have to do?

blurbendy
 2 years ago
Best ResponseYou've already chosen the best response.0To 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

blurbendy
 2 years ago
Best ResponseYou've already chosen the best response.0you 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

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