Cho ma trận
$\begin{pmatrix} a & 0 & b & a \\ b & b & 0 & a \\ b & a & 0 & b \\ a & b & 0 & a \end{pmatrix}$
Tính $\det(A)$
Edited by phudinhgioihan, 10-11-2013 - 17:03.
Cho ma trận
$\begin{pmatrix} a & 0 & b & a \\ b & b & 0 & a \\ b & a & 0 & b \\ a & b & 0 & a \end{pmatrix}$
Tính $\det(A)$
Edited by phudinhgioihan, 10-11-2013 - 17:03.
Tính $\det(A)$
Khai triển Laplace:
$\begin{vmatrix} a & 0 & b & a \\ b & b & 0 & a \\ b & a & 0 & b \\ a & b & 0 & a \end{vmatrix}=b\begin{vmatrix} b &b &a \\ b& a& b\\ a& b &a \end{vmatrix}=b\left [ b(a^2-b^2)-b(ba-ab)+a(b^2-a^2) \right ]=-b(a+b)(a-b)^2$
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