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matrix dimension #10

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matrix dimension #10

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2 changes: 1 addition & 1 deletion chapter02.ipynb
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Expand Up @@ -29,7 +29,7 @@
"\n",
"## 消元矩阵\n",
"\n",
"上一讲我们学习了矩阵乘以向量的方法，有三个列向量的矩阵乘以另一个向量，按列的线性组合可以写作$\\Bigg[v_1\\ v_2\\ v_3\\Bigg]\\begin{bmatrix}3\\\\4\\\\5\\end{bmatrix}=3v_1+4v_2+5v_3$。\n",
"上一讲我们学习了矩阵乘以向量的方法，这里是1×3的行向量乘以3×1的列向量，按列的线性组合可以写作$\\Bigg[v_1\\ v_2\\ v_3\\Bigg]\\begin{bmatrix}3\\\\4\\\\5\\end{bmatrix}=3v_1+4v_2+5v_3$（等式右边是一个数值，数值可以看作1×1的矩阵）。\n",
"\n",
"但现在我们希望用矩阵乘法表示行操作，则有$\\begin{bmatrix}1&2&7\\end{bmatrix}\\begin{bmatrix}&row_1&\\\\&row_2&\\\\&row_3&\\end{bmatrix}=1row_1+2row_2+7row_3$。易看出这里是一个行向量从左边乘以矩阵，这个行向量按行操作矩阵的行向量，并将其合成为一个矩阵行向量的线性组合。\n",
"\n",
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