7:56 if U is an upper triangular matrix with 1’s in the diagonal and L be a lower triangular matrix with 1’s in the diagonal, wouldn’t the product U*L be necessarily have a 1 in its first entry? Meaning if U*L = A then a_11 must be a 1. If that is the case, how did you come up with a -8 or a -2 in your original example?
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7:56 if U is an upper triangular matrix with 1’s in the diagonal and L be a lower triangular matrix with 1’s in the diagonal, wouldn’t the product U*L be necessarily have a 1 in its first entry? Meaning if U*L = A then a_11 must be a 1. If that is the case, how did you come up with a -8 or a -2 in your original example?
Depends on the order in which you multiply them.