<p>已知2阶矩阵<img src="https://file.gaojiufeng.cn/learnAppQuestion/69/b2/69b28f9d617912b6477cbed002a8a4e0.jpg" style="width: 100%;height: auto;">的行列式<img src="https://file.gaojiufeng.cn/learnAppQuestion/a8/d5/a8d504e4ed5f5fe60cf0d5078e149e8e.jpg" style="width: 100%;height: auto;">则<img src="https://file.gaojiufeng.cn/learnAppQuestion/40/ef/40ef4627711b4daaffff5b26f10acc89.jpg" style="width: 100%;height: auto;">().</p>