Let $f(x) = x^2 + x \sin x - \cos x$. Then

If $f(x) = \begin{cases} x e^{-\left( \frac{1}{|x|} + \frac{1}{x} \right)}, & x \ne 0 \\ 0, & x = 0 \end{cases}$,then $f(x)$ is

If $f(x) = \frac{1 - \sin x}{\log(1 + \pi^2 - 4\pi x + 4x^2)}$ is continuous at $x = \frac{\pi}{2}$,then $f\left(\frac{\pi}{2}\right) = $

If a real valued function $f(x) = \begin{cases} (1+\sin x)^{\operatorname{cosec} x}, & -\pi/2 < x < 0 \\ a, & x=0 \\ \frac{e^{2/x}+e^{3/x}}{a e^{2/x}+b e^{3/x}}, & 0 < x < \pi/2 \end{cases}$ is continuous at $x=0$,then $ab=$

If $f(x) = \begin{cases} \frac{k \cos x}{\pi - 2x}, & x \neq \frac{\pi}{2} \\ 3, & x = \frac{\pi}{2} \end{cases}$ is continuous at $x = \frac{\pi}{2}$,then the value of $k$ is equal to . . . . . . .

Consider $f(x) = [x]|x^3 - 2x^2 - x + 2|$ in $[-\frac{3}{2}, \frac{9}{2}]$. The number of points where $f(x)$ is discontinuous is (where $[.]$ denotes the greatest integer function).