If $f(x) = \begin{cases} x \sin \frac{1}{x}, & x \neq 0 \\ k, & x = 0 \end{cases}$ is continuous at $x = 0$,then the value of $k$ is

The function defined by $f(x) = \begin{cases} \frac{x-4}{|x-4|} + a, & x < 4 \\ a + b, & x = 4 \\ \frac{x-4}{|x-4|} + b, & x > 4 \end{cases}$ is continuous at $x = 4$,then:

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 $ab=$

Which of the following statements is true for the graph of the function $f(x) = \log x$?

Find the points of discontinuity of $f,$ where $f(x) = \begin{cases} \frac{\sin x}{x}, & \text{if } x < 0 \\ x + 1, & \text{if } x \ge 0 \end{cases}$