矩阵的加减法

示例1:

将矩阵相加。

$［\begin{array}{rr}\hfill 1& \hfill 5\\ \hfill -4& \hfill 3.\end{array}］+［\begin{array}{rr}\hfill 2& \hfill -1\\ \hfill 4& \hfill -1\end{array}］$

首先注意两个加数都是$2\times 2$矩阵，我们可以把它们相加。

$［\begin{array}{rr}\hfill 1& \hfill 5\\ \hfill -4& \hfill 3.\end{array}］+［\begin{array}{rr}\hfill 2& \hfill -1\\ \hfill 4& \hfill -1\end{array}］=［\begin{array}{rr}\hfill 1+2& \hfill 5+（-1）\\ \hfill -4+4& \hfill 3.+（-1）\end{array}］$

$=［\begin{array}{rr}\hfill 3.& \hfill 4\\ \hfill 0& \hfill 2\end{array}］$

示例2:

减去。

$［\begin{array}{rrr}\hfill 4& \hfill 5& \hfill 6\\ \hfill 2& \hfill 3.& \hfill 4\end{array}］-［\begin{array}{rrr}\hfill 2& \hfill 4& \hfill 6\\ \hfill 1& \hfill 2& \hfill 3.\end{array}］$

减去相应的项。

$［\begin{array}{rrr}\hfill 4& \hfill 5& \hfill 6\\ \hfill 2& \hfill 3.& \hfill 4\end{array}］-［\begin{array}{rrr}\hfill 2& \hfill 4& \hfill 6\\ \hfill 1& \hfill 2& \hfill 3.\end{array}］=［\begin{array}{rrr}\hfill 4-2& \hfill 5-4& \hfill 6-6\\ \hfill 2-1& \hfill 3.-2& \hfill 4-3.\end{array}］$

$=［\begin{array}{rrr}\hfill 2& \hfill 1& \hfill 0\\ \hfill 1& \hfill 1& \hfill 1\end{array}］$