If $\omega$ is a cube root of unity, then find the value of determinant $\begin{vmatrix} 1+\omega &\omega^{2} &-\omega \\ 1+\omega^{2}&\omega &-\omega^{2} \\ \omega^{2}+\omega&\omega &-\omega^{2} \end{vmatrix}$
If $x, y, z$ are distinct real numbers, then
$$
\begin{vmatrix}
x & x^{2} & 2 + x^{3} \\
y & y^{2} & 2 + y^{3} \\
z & z^{2} & 2 + z^{3}
\end{vmatrix} = 0
$$
Then find $xyz$.
If $a \ne p$, $b \ne q$, $c \ne r$ and
$\left|\begin{matrix}
p & b & c \\
a & q & c \\
a & b & r
\end{matrix}\right| = 0$,
then the value of $\frac{p}{p-a} + \frac{q}{q-b} + \frac{r}{r-c}$ is
Solution:
Given
$\left|\begin{matrix}
p & b & c \\
a & q & c \\
a & b & r
\end{matrix}\right| = 0,$
the rows are linearly dependent.
Using the determinant identity, we get
$\frac{p}{p-a} + \frac{q}{q-b} + \frac{r}{r-c} = 1.$
The value of the determinant of the following matrix at $x=2026$ is:
$\left|\begin{array}{ccc}
x & x+1 & x+3\\
x+1 & x+3 & x+6\\
x+3 & x+6 & x+10
\end{array}\right|$
The number of values of $\theta$ in the interval $[0,2\pi]$ for which the following homogeneous system of equations has a non-trivial solution is:$x+(\sin\theta)y+(\cos\theta)z=0$$x+(\cos\theta)y+(\sin\theta)z=0$$x-(\sin\theta)y-(\cos\theta)z=0$
A homogeneous system has a non-trivial solution $\iff$ the determinant of its coefficient matrix is $0$.
Coefficient matrix $A=\begin{bmatrix}4 & k & 2\\ k & 4 & 1\\ 2 & 2 & 1\end{bmatrix}$. Hence,
$$
\det(A)=
\begin{vmatrix}
4 & k & 2\\
k & 4 & 1\\
2 & 2 & 1
\end{vmatrix}
=-(k-4)(k-2).
$$
Setting $\det(A)=0 \Rightarrow -(k-4)(k-2)=0 \Rightarrow k=2 \text{ or } k=4.$
Therefore, the number of values of $k$ is $\boxed{2}$.