矩陣指數計算器

逐步計算矩陣指數

對於給定的矩陣 $$$A$$$,本計算器將求其矩陣指數 $$$e^A$$$,並顯示步驟。

相關計算器: 矩陣冪計算器

A

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您的輸入

$$$e^{\left[\begin{array}{cc}3 & -10\\1 & -4\end{array}\right]}$$$

解答

首先,將矩陣對角化(步驟請參見 matrix diagonalization calculator)。

$$$P = \left[\begin{array}{cc}5 & 2\\1 & 1\end{array}\right]$$$

$$$D = \left[\begin{array}{cc}1 & 0\\0 & -2\end{array}\right]$$$

$$$P$$$ 的逆矩陣: $$$P^{-1} = \left[\begin{array}{cc}\frac{1}{3} & - \frac{2}{3}\\- \frac{1}{3} & \frac{5}{3}\end{array}\right]$$$ (步驟請參見 逆矩陣計算器).

現在,$$$e^{\left[\begin{array}{cc}3 & -10\\1 & -4\end{array}\right]} = e^{\left[\begin{array}{cc}5 & 2\\1 & 1\end{array}\right]\cdot \left[\begin{array}{cc}1 & 0\\0 & -2\end{array}\right]\cdot \left[\begin{array}{cc}\frac{1}{3} & - \frac{2}{3}\\- \frac{1}{3} & \frac{5}{3}\end{array}\right]} = \left[\begin{array}{cc}5 & 2\\1 & 1\end{array}\right]\cdot e^{\left[\begin{array}{cc}1 & 0\\0 & -2\end{array}\right]}\cdot \left[\begin{array}{cc}\frac{1}{3} & - \frac{2}{3}\\- \frac{1}{3} & \frac{5}{3}\end{array}\right]$$$

對角矩陣的矩陣指數是將其對角元素分別取指數所得的矩陣:$$$e^{\left[\begin{array}{cc}1 & 0\\0 & -2\end{array}\right]} = \left[\begin{array}{cc}e & 0\\0 & e^{-2}\end{array}\right]$$$

因此,$$$e^{\left[\begin{array}{cc}3 & -10\\1 & -4\end{array}\right]} = \left[\begin{array}{cc}5 & 2\\1 & 1\end{array}\right]\cdot \left[\begin{array}{cc}e & 0\\0 & e^{-2}\end{array}\right]\cdot \left[\begin{array}{cc}\frac{1}{3} & - \frac{2}{3}\\- \frac{1}{3} & \frac{5}{3}\end{array}\right]$$$

最後,將矩陣相乘:

$$$\left[\begin{array}{cc}5 & 2\\1 & 1\end{array}\right]\cdot \left[\begin{array}{cc}e & 0\\0 & e^{-2}\end{array}\right] = \left[\begin{array}{cc}5 e & \frac{2}{e^{2}}\\e & e^{-2}\end{array}\right]$$$(步驟請參見 矩陣乘法計算器)。

$$$\left[\begin{array}{cc}5 e & \frac{2}{e^{2}}\\e & e^{-2}\end{array}\right]\cdot \left[\begin{array}{cc}\frac{1}{3} & - \frac{2}{3}\\- \frac{1}{3} & \frac{5}{3}\end{array}\right] = \left[\begin{array}{cc}\frac{-2 + 5 e^{3}}{3 e^{2}} & \frac{10 - 10 e^{3}}{3 e^{2}}\\\frac{-1 + e^{3}}{3 e^{2}} & \frac{5 - 2 e^{3}}{3 e^{2}}\end{array}\right]$$$(步驟請參見 矩陣乘法計算器)。

答案

$$$e^{\left[\begin{array}{cc}3 & -10\\1 & -4\end{array}\right]} = \left[\begin{array}{cc}\frac{-2 + 5 e^{3}}{3 e^{2}} & \frac{10 - 10 e^{3}}{3 e^{2}}\\\frac{-1 + e^{3}}{3 e^{2}} & \frac{5 - 2 e^{3}}{3 e^{2}}\end{array}\right]\approx \left[\begin{array}{cc}4.440246191940667 & -8.609821817408108\\0.860982181740811 & -1.586629080245009\end{array}\right]$$$A