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@@ -65,6 +65,7 @@ $$
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设矩阵
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$$
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+
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A=\begin{bmatrix}
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{a_{11}}&{a_{12}}&{\cdots}&{a_{1n}}\\
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{a_{21}}&{a_{22}}&{\cdots}&{a_{2n}}\\
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@@ -78,7 +79,9 @@ A=\begin{bmatrix}
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\end{bmatrix}
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$$
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有
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+
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$$
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+
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A\pm\;B=\begin{bmatrix}
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{a_{11}\pm\;b_{11}}&{a_{12}\pm\;b_{12}}&{\cdots}&{a_{1n}\pm\;b_{1n}}\\
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{a_{21}\pm\;b_{21}}&{a_{22}\pm\;b_{22}}&{\cdots}&{a_{2n}\pm\;b_{2n}}\\
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@@ -95,6 +98,7 @@ $$
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- 结合律:$(A+B)+C=A+(B+C)$
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**栗子:**
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+
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$$
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A=\begin{bmatrix}{1}&{0}&{1}\\{1}&{0}&{0}\\{0}&{0}&{1}\\\end{bmatrix},B=\begin{bmatrix}{0}&{0}&{1}\\{1}&{0}&{0}\\{0}&{0}&{1}\\\end{bmatrix}\\
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A+B= B+A =\begin{bmatrix}{1}&{0}&{2}\\{2}&{0}&{0}\\{0}&{0}&{2}\\\end{bmatrix}
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@@ -109,6 +113,7 @@ $$
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标量乘法即一个矩阵和一个数相乘。运算法则:将矩阵的每一个元素都乘上这个数即可
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**栗子:**
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+
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$$
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A = \begin{bmatrix}{1}&{2}\\{3}&{4}\\\end{bmatrix}\\
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2\times A= 2\times \begin{bmatrix}{1}&{2}\\{3}&{4}\\\end{bmatrix} = \begin{bmatrix}{2 \times 1}&{2 \times 2}\\{2 \times 3}&{2 \times 4}\\\end{bmatrix} =\begin{bmatrix}{2}&{4}\\{6}&{8}\\\end{bmatrix}
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