diff --git a/linear-algebra/knowledge/2-matrix/matrix.pdf b/linear-algebra/knowledge/2-matrix/matrix.pdf
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--- a/linear-algebra/knowledge/2-matrix/matrix.tex
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@@ -747,6 +747,4 @@ $$(a_1,a_2,\cdots,a_n)\left(\begin{array}{c}
 
 对于任何矩阵都能通过初等列变换变为行阶梯形矩阵和行最简形矩阵，再通过列变换可以变为\textbf{标准形}：左上角是一个单位矩阵，其他元全部是0。
 
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