定義
![可逆矩陣](/img/b/848/wZwpmL1YDNwYzMwMzMzIDN0UTMyITNykTO0EDMwAjMwUzLzMzL4QzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![可逆矩陣](/img/e/be5/wZwpmL3IDMzMDM5ETOxMzM1UTM1QDN5MjM5ADMwAjMwUzLxkzL1IzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![可逆矩陣](/img/2/593/wZwpmL0YTM4kDO1UTOxMzM1UTM1QDN5MjM5ADMwAjMwUzL1kzL3gzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![可逆矩陣](/img/4/6ea/wZwpmLzcDMykzM1QTM2EzM1UTM1QDN5MjM5ADMwAjMwUzL0EzL0IzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/b/b17/wZwpmLyIDN2UTN1MzNwIDN0UTMyITNykTO0EDMwAjMwUzLzczL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/5/8fe/wZwpmLwIzN1gDO1ADO3EDN0UTMyITNykTO0EDMwAjMwUzLwgzLxAzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/5/dab/wZwpmLzEzN0gTOxYjM2EzM1UTM1QDN5MjM5ADMwAjMwUzL2IzLyYzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
設是數域,,若存在,使得,為單位陣,則稱為可逆陣,為的逆矩陣,記為。若方陣的逆陣存在,則稱為可逆矩陣或非奇異矩陣。
性質
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
(1)若為可逆矩陣,則的逆矩陣是唯一的。
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/5/8fe/wZwpmLwIzN1gDO1ADO3EDN0UTMyITNykTO0EDMwAjMwUzLwgzLxAzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/b/848/wZwpmL1YDNwYzMwMzMzIDN0UTMyITNykTO0EDMwAjMwUzLzMzL4QzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![可逆矩陣](/img/a/e3f/wZwpmL1AzN1kDO3ATMwEDN0UTMyITNykTO0EDMwAjMwUzLwEzL4UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![可逆矩陣](/img/1/1c2/wZwpmLzcjM3QDM4gzNxMzM1UTM1QDN5MjM5ADMwAjMwUzL4czLzQzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
(2)設、是數域上的階矩陣,。
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/7/fbc/wZwpmL4UTM4kDOxgTMzEzM1UTM1QDN5MjM5ADMwAjMwUzL4EzL0QzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/8/b53/wZwpmL3czNzIDOzMzNwMzM1UTM1QDN5MjM5ADMwAjMwUzLzczL0AzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![可逆矩陣](/img/4/915/wZwpmLxEzNwIzN1kDOxMzM1UTM1QDN5MjM5ADMwAjMwUzL5gzL1czLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/f/e31/wZwpmL2cTNwEjMyUTMxMzM1UTM1QDN5MjM5ADMwAjMwUzL1EzLzIzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
①若可逆,則和也可逆,且,;
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/e/813/wZwpmL4UDOzEDNwcjNxMzM1UTM1QDN5MjM5ADMwAjMwUzL3YzL2MzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/7/135/wZwpmLyQjMzQTN2cjN1IDN0UTMyITNykTO0EDMwAjMwUzL3YzLyYzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/2/111/wZwpmLzcDNxkzM2YzNwMzM1UTM1QDN5MjM5ADMwAjMwUzL2czLyEzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/1/da5/wZwpmL2ITO3UDMwUTMxMzM1UTM1QDN5MjM5ADMwAjMwUzL1EzLxMzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
②若可逆,則可逆,且;
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/5/8fe/wZwpmLwIzN1gDO1ADO3EDN0UTMyITNykTO0EDMwAjMwUzLwgzLxAzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/7/135/wZwpmLyQjMzQTN2cjN1IDN0UTMyITNykTO0EDMwAjMwUzL3YzLyYzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/a/a55/wZwpmL1MDO3gDO0MzNwMzM1UTM1QDN5MjM5ADMwAjMwUzLzczL0QzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
③、均可逆。
常用方法
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
(1)判斷或證明 可逆的常用方法:
![可逆矩陣](/img/1/f64/wZwpmLzYzM5IzM1YzMxMzM1UTM1QDN5MjM5ADMwAjMwUzL2MzL2UzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
①證明;
![可逆矩陣](/img/5/8fe/wZwpmLwIzN1gDO1ADO3EDN0UTMyITNykTO0EDMwAjMwUzLwgzLxAzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/4/6ea/wZwpmLzcDMykzM1QTM2EzM1UTM1QDN5MjM5ADMwAjMwUzL0EzL0IzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
②找一個同階矩陣,驗證;
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
③證明的行向量(或列向量)線性無關。
![可逆矩陣](/img/7/fbc/wZwpmL4UTM4kDOxgTMzEzM1UTM1QDN5MjM5ADMwAjMwUzL4EzL0QzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
(2)求 的方法:
![可逆矩陣](/img/b/af8/wZwpmL0ITNyATM5EjM2EzM1UTM1QDN5MjM5ADMwAjMwUzLxIzL4UzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![可逆矩陣](/img/2/13a/wZwpmL0UTOyUzNwkDNzEzM1UTM1QDN5MjM5ADMwAjMwUzL5QzLxgzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
①公式法:,其中為矩陣的伴隨矩陣。
![可逆矩陣](/img/d/bde/wZwpmL3QjNxkTN2ITOxMzM1UTM1QDN5MjM5ADMwAjMwUzLykzLyQzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![可逆矩陣](/img/c/c8f/wZwpmL3gTMycjM4QTOwADN0UTMyITNykTO0EDMwAjMwUzL0kzL3MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/b/b17/wZwpmLyIDN2UTN1MzNwIDN0UTMyITNykTO0EDMwAjMwUzLzczL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/b/b17/wZwpmLyIDN2UTN1MzNwIDN0UTMyITNykTO0EDMwAjMwUzLzczL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![可逆矩陣](/img/7/fbc/wZwpmL4UTM4kDOxgTMzEzM1UTM1QDN5MjM5ADMwAjMwUzL4EzL0QzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
②初等變換法:對作初等變換,將化為單位陣,單位矩陣就化為。