1.4.27 Matrix transformations

\( \underline{\mathrm{y}_{\text {word: }}} \) Calculate the value of the function from the matrix. \[ \cos \left(\frac{\pi}{2} A\right), \quad \text { where } A=\left(\begin{array}{ccc} 1 & 1 & 1 \\ -8 & -5 & -4 \\ 4 & 2 & 1 \end{array}\right) \]