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Find the products AB and BA to determine whether B is the multiplicative inverse of A.?
 one year ago
 one year ago
Find the products AB and BA to determine whether B is the multiplicative inverse of A.?
 one year ago
 one year ago

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HoaBest ResponseYou've already chosen the best response.0
I don't know why we have to find the product of AB and then BA. My work is use GaussJordan method to figure out inverse of A and then compare to B. and dw:1360901929122:dw is inverse of A, it is not a multiply matrix of B .
 one year ago

BAdhiBest ResponseYou've already chosen the best response.0
This uses the definition of the multiplicative inverse. ie if and only if, $$AB=BA=I$$ A is the multiplicative inverse of B So find the values of AB and BA and see whether they are equal to identity matrix
 one year ago

phiBest ResponseYou've already chosen the best response.1
Find the products AB and BA They want you to practice multiplying 2 matrices. can you multiply A*B ?
 one year ago

gjhfdfgBest ResponseYou've already chosen the best response.1
The bottom column of B is suppose to be 0 1 1, my mistake. But I multiplied a * b & I got, [1 0 0] [0 1 0] [0 0 1]
 one year ago

phiBest ResponseYou've already chosen the best response.1
OK, the matrix with 1's on the diagonal is the identity matrix (called I (eye)) a * I will give you a also, if you know a * b = I then you know b is the *inverse* of a you also know b*a= I (but I think they want you to multiply it out and see that it is) and we could just as well say a is the *inverse* of b \[ A^{1} A = I \] (People use capital letters for matrices (bold face if you can). the use lower case, bold letters for vectors)
 one year ago

gjhfdfgBest ResponseYou've already chosen the best response.1
Wouldnt it be B = A^1?
 one year ago

phiBest ResponseYou've already chosen the best response.1
you mean "wouldn't it be \[ B = A^{1} \] the 1 is not an exponent, but means *inverse* You can say that. But the inverse of the inverse \[ (A^{1})^{1} = A\] if we take the inverse of both sides \[ B^{1} = (A^{1})^{1} = A \] or \[ A = B^{1} \] which says A is the inverse of B (or vice versa)
 one year ago

gjhfdfgBest ResponseYou've already chosen the best response.1
Ah okay, what would it mean if they "=" had a slash through it?
 one year ago

gjhfdfgBest ResponseYou've already chosen the best response.1
Got it, thank you for the help.!
 one year ago
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