Question

Write the value of the determinant $\left[\begin{array}{cc}p& p+1\\ p-1& p\end{array}\right]$
when $p=1342$

Answer 1

We have, $\left[\begin{array}{cc}p& p+1\\ p-1& p\end{array}\right]$
$=p^2-(p+1)(p-1)$
$=p^2-(p^2-1)$
$=1$