The value of $\left| {\,\begin{array}{*{20}{c}}1&{\cos (\beta - \alpha )}&{\cos (\gamma - \alpha )}\\{\cos (\alpha - \beta )}&1&{\cos (\gamma - \beta )}\\{\cos (\alpha - \gamma )}&{\cos (\beta - \gamma )}&1\end{array}} \right|$ is
${\left| {\,\begin{array}{*{20}{c}}{\cos \alpha }&{\sin \alpha }&1\\{\cos \beta }&{\sin \beta }&1\\{\cos \gamma }&{\sin \gamma }&1\end{array}\,} \right|^2}$
${\left| {\,\begin{array}{*{20}{c}}{\sin \alpha }&{\cos \alpha }&0\\{\sin \beta }&{\cos \beta }&0\\{\sin \gamma }&{\cos \gamma }&0\end{array}\,} \right|^2}$
${\left| {\,\begin{array}{*{20}{c}}{\cos \alpha }&{\sin \alpha }&0\\{\sin \beta }&0&{\cos \beta }\\0&{\cos \gamma }&{\sin \gamma }\end{array}\,} \right|^2}$
None of these
If $A\, = \,\left[ \begin{gathered}
1\ \ \ \,1\ \ \ \,2\ \ \ \hfill \\
0\ \ \ \,2\ \ \ \,1\ \ \ \hfill \\
1\ \ \ \,0\ \ \ \,2\ \ \ \hfill \\
\end{gathered} \right]$ and $A^3 = (aA-I) (bA-I)$,where $a, b$ are integers and $I$ is a $3 × 3$ unit matrix then value of $(a + b)$ is equal to
If $\alpha ,\beta \ne 0$ and $f\left( n \right) = {\alpha ^n} + {\beta ^n}$ and $\left| {\begin{array}{*{20}{c}}3&{1 + f\left( 1 \right)}&{1 + f\left( 2 \right)}\\{1 + f\left( 1 \right)}&{1 + f\left( 2 \right)}&{1 + f\left( 3 \right)}\\{1 + f\left( 2 \right)}&{1 + f\left( 3 \right)}&{1 + f\left( 4 \right)}\end{array}} \right|\; = K{\left( {1 - \alpha } \right)^2}$ ${\left( {1 - \beta } \right)^2}{\left( {\alpha - \beta } \right)^2}$ ,then $K=$ . . . . . .
The values of $\lambda$ and $\mu$ for which the system of linear equations
$x+y+z=2$
$x+2 y+3 z=5$
$x+3 y+\lambda z=\mu$
has infinitely many solutions are, respectively
The values of $x $ in the following determinant equation, $\left| {\,\begin{array}{*{20}{c}}{a + x}&{a - x}&{a - x}\\{a - x}&{a + x}&{a - x}\\{a - x}&{a - x}&{a + x}\end{array}\,} \right| = 0$ are