Let $f(x) = \begin{vmatrix} \cos x & \sin x & \cos x \\ \cos 2x & \sin 2x & 2\cos 2x \\ \cos 3x & \sin 3x & 3\cos 3x \end{vmatrix}$. Then $f'\left(\frac{\pi}{2}\right) = $

Let $f(x) = \begin{vmatrix} \cos x & x & 1 \\ 2 \sin x & x^2 & 2x \\ \tan x & x & 1 \end{vmatrix}$. Then $\lim_{x \to 0} \frac{f'(x)}{x} =$

Suppose $\left| \begin{array}{cc} f'(x) & f(x) \\ f''(x) & f'(x) \end{array} \right| = 0$ where $f(x)$ is a continuously differentiable function with $f'(x) \ne 0$ and satisfies $f(0) = 1$ and $f'(0) = 2$. Then the number of solution$(s)$ of the equation $f(x) = x^2$ is equal to:

$A$ is a singular matrix of order $5$. $B$ is another matrix having the rank $\rho(B)$ equal to the rank $\rho(A)$,and $B$ has a non-zero minor of order $3$. Then which one of the following is true?

If $f(x) = \begin{vmatrix} x^3-x & 2e^{2x} & \sin x^2 \\ \cos(2x) & x+x^2 & e^{-x} \\ \tan 3x & \ln(1-2x) & x^2+x+1 \end{vmatrix}$,then $f'(0)$ is equal to:

Let $f(x) = \left| \begin{array}{ccc} 1 + \sin^2 x & \cos^2 x & 4 \sin 2x \\ \sin^2 x & 1 + \cos^2 x & 4 \sin 2x \\ \sin^2 x & \cos^2 x & 1 + 4 \sin 2x \end{array} \right|$,then the maximum value of $f(x)$ is: