diff --git a/content/mathematics/《线性代数》克莱姆法则.md b/content/mathematics/《线性代数》克莱姆法则.md new file mode 100644 index 0000000..03acf2d --- /dev/null +++ b/content/mathematics/《线性代数》克莱姆法则.md @@ -0,0 +1,78 @@ +--- +title: "《线性代数》克莱姆法则" +date: 2023-08-11T21:07:47+08:00 + +--- + +## 克莱姆法则 + +克莱姆法则并非计算线性方程组的最好方法(高斯消元法),但能够加深对线性方程组的理解 + + +对于一个线性方程组 +$$ +\begin{cases} + 3x+2y &=-4 \\\\ + -1x+2y &=-2 +\end{cases} +$$ + +可以将其看作对向量的一个已知的矩阵变换,且结果已知 + +$$ +\begin{bmatrix} + 3 & 2 \\\\ + -1 & 2 +\end{bmatrix} +\begin{bmatrix} + x \\\\ + y +\end{bmatrix} = +\begin{bmatrix} + -4 \\\\ + -2 +\end{bmatrix} +$$ + +![](../../images/%E6%95%B0%E5%AD%A6/%E3%80%8A%E7%BA%BF%E6%80%A7%E4%BB%A3%E6%95%B0%E3%80%8B%E5%85%8B%E8%8E%B1%E5%A7%86%E6%B3%95%E5%88%99/%E7%BA%BF%E6%80%A7%E6%96%B9%E7%A8%8B%E7%BB%84%E8%BD%AC%E5%8C%96.gif) + +$$ +x\begin{bmatrix} + 3 \\\\ + -1 +\end{bmatrix} + +y\begin{bmatrix} + 2 \\\\ + 2 +\end{bmatrix} = +\begin{bmatrix} + -4 \\\\ + -2 +\end{bmatrix} +$$ + +在计算时不能将点乘的结果视为x或y的坐标,因为点乘会随着线性变换而改变结果甚至正负性,但对于不改变点积的正交变换(基向量在变换后依然保持单位长度且相互垂直)则可以使用 + + +![](../../images/%E6%95%B0%E5%AD%A6/%E3%80%8A%E7%BA%BF%E6%80%A7%E4%BB%A3%E6%95%B0%E3%80%8B%E5%85%8B%E8%8E%B1%E5%A7%86%E6%B3%95%E5%88%99/%E6%AD%A3%E4%BA%A4%E7%9F%A9%E9%98%B5%E4%B8%8B%E7%82%B9%E7%A7%AF.gif) + +面积/体积与坐标值的关系 + +![](../../images/%E6%95%B0%E5%AD%A6/%E3%80%8A%E7%BA%BF%E6%80%A7%E4%BB%A3%E6%95%B0%E3%80%8B%E5%85%8B%E8%8E%B1%E5%A7%86%E6%B3%95%E5%88%99/%E9%9D%A2%E7%A7%AF.gif) + +![](../../images/%E6%95%B0%E5%AD%A6/%E3%80%8A%E7%BA%BF%E6%80%A7%E4%BB%A3%E6%95%B0%E3%80%8B%E5%85%8B%E8%8E%B1%E5%A7%86%E6%B3%95%E5%88%99/%E4%BD%93%E7%A7%AF.gif) + +根据面积关系可以求出Y + +![](../../images/%E6%95%B0%E5%AD%A6/%E3%80%8A%E7%BA%BF%E6%80%A7%E4%BB%A3%E6%95%B0%E3%80%8B%E5%85%8B%E8%8E%B1%E5%A7%86%E6%B3%95%E5%88%99/%E6%B1%82Y.gif) + +X的求取同理 + +![](../../images/%E6%95%B0%E5%AD%A6/%E3%80%8A%E7%BA%BF%E6%80%A7%E4%BB%A3%E6%95%B0%E3%80%8B%E5%85%8B%E8%8E%B1%E5%A7%86%E6%B3%95%E5%88%99/%E6%B1%82X.gif) + +上述对XY的求取方式就是克莱姆法则 + +在三维下同样适用 + +![](../../images/%E6%95%B0%E5%AD%A6/%E3%80%8A%E7%BA%BF%E6%80%A7%E4%BB%A3%E6%95%B0%E3%80%8B%E5%85%8B%E8%8E%B1%E5%A7%86%E6%B3%95%E5%88%99/%E4%B8%89%E7%BB%B4.gif) + diff --git a/static/images/数学/《线性代数》克莱姆法则/三维.gif b/static/images/数学/《线性代数》克莱姆法则/三维.gif new file mode 100644 index 0000000..589b793 Binary files /dev/null and b/static/images/数学/《线性代数》克莱姆法则/三维.gif differ diff --git a/static/images/数学/《线性代数》克莱姆法则/体积.gif b/static/images/数学/《线性代数》克莱姆法则/体积.gif new file mode 100644 index 0000000..5f41c43 Binary files /dev/null and b/static/images/数学/《线性代数》克莱姆法则/体积.gif differ diff --git a/static/images/数学/《线性代数》克莱姆法则/正交矩阵下点积.gif b/static/images/数学/《线性代数》克莱姆法则/正交矩阵下点积.gif new file mode 100644 index 0000000..ccb7eef Binary files /dev/null and b/static/images/数学/《线性代数》克莱姆法则/正交矩阵下点积.gif differ diff --git a/static/images/数学/《线性代数》克莱姆法则/求X.gif b/static/images/数学/《线性代数》克莱姆法则/求X.gif new file mode 100644 index 0000000..437a541 Binary files /dev/null and b/static/images/数学/《线性代数》克莱姆法则/求X.gif differ diff --git a/static/images/数学/《线性代数》克莱姆法则/求Y.gif b/static/images/数学/《线性代数》克莱姆法则/求Y.gif new file mode 100644 index 0000000..3138c02 Binary files /dev/null and b/static/images/数学/《线性代数》克莱姆法则/求Y.gif differ diff --git a/static/images/数学/《线性代数》克莱姆法则/线性方程组转化.gif b/static/images/数学/《线性代数》克莱姆法则/线性方程组转化.gif new file mode 100644 index 0000000..9218d0c Binary files /dev/null and b/static/images/数学/《线性代数》克莱姆法则/线性方程组转化.gif differ diff --git a/static/images/数学/《线性代数》克莱姆法则/面积.gif b/static/images/数学/《线性代数》克莱姆法则/面积.gif new file mode 100644 index 0000000..b5c878a Binary files /dev/null and b/static/images/数学/《线性代数》克莱姆法则/面积.gif differ