If $a, b, c$ are sides of a scalene triangle,then the value of $\left| \begin{array}{ccc} a & b & c \\ b & c & a \\ c & a & b \end{array} \right|$ is

If $A, B, C$ are the angles of a triangle,then the system of equations $-x + y \cos C + z \cos B = 0$,$x \cos C - y + z \cos A = 0$,$x \cos B + y \cos A - z = 0$ have

The matrix $A = \begin{bmatrix} a & -1 & 4 \\ -3 & 0 & 1 \\ -1 & 1 & 2 \end{bmatrix}$ is not invertible only if $a =$

Let $M=\left\{A=\begin{bmatrix} a & b \\ c & d \end{bmatrix} : a, b, c, d \in \{\pm 3, \pm 2, \pm 1, 0\}\right\}$. Define $f: M \rightarrow \mathbb{Z}$ as $f(A) = \det(A)$ for all $A \in M$,where $\mathbb{Z}$ is the set of all integers. Then the number of $A \in M$ such that $f(A) = 15$ is equal to $.....$

The value of $a$ for which the system of equations $a^3x + (a + 1)^3y + (a + 2)^3z = 0$,$ax + (a + 1)y + (a + 2)z = 0$,and $x + y + z = 0$ has a non-zero solution is:

If $A_n = \begin{bmatrix} 1-n & n \\ n & 1-n \end{bmatrix}$,then $|A_1| + |A_2| + \dots + |A_{2021}| = $