QMA-Matrix HELP!! (1 Viewer)

[studymon]

why is the determinant of the upper triangular matrix equal to the product of the diagonal elements???

...because i tried to calculate it using the normal procedures in finding a determinant on the triangular matrix and i got a different ans =S ...or are they meant to be the same???

thanks,,
studymon

 

[Azamakumar]

Your arithmetic must've been wrong. A cofactor expansion of that matrix would see everything not on the main diagonal multiplied by a 0, which could be either in the determinant of the 2x2 matrix or by the coefficient multiplying the 2x2 matrix.