Question

Помогите срочно решить 1 и 4 номер

Answer 1

т.к. A= $\left[\begin{array}{ccc}2&1\\1&0\\1&3&\end{array}\right]$, то

[A^T[/tex]​ = $\left[\begin{array}{ccc}2&1&1\\1&0&3\end{array}\right]$

$A*A^T=\left[\begin{array}{ccc}2&1\\1&0\0\\1&3\end{array}\right] * \left[\begin{array}{ccc}2&1&1\\1&0&3\end{array}\right] = \left[\begin{array}{ccc}5&2&5\\2&1&1\\5&1&10\end{array}\right]$

Найдем det$\left[\begin{array}{ccc}5&2&5\\2&1&1\\5&1&10\end{array}\right]$ =

=

$5*\left[\begin{array}{ccc}1&1\\1&10\end{array}\right] - 2* \left[\begin{array}{ccc}2&1\\5&10\end{array}\right] + 5*\left[\begin{array}{ccc}2&1\\5&1\end{array}\right] = 5*(10-1)-2*(20-5)+5*(5-2)=30$

Ответ. 30