The incentre of the triangle whose vertices are $P(0,3,0), Q(0,0,4)$ and $R(0,3,4)$ is

A random variable $X$ has the following probability distribution

The mean and variance of X are respectively

$\lim _\limits{x \rightarrow 0} \frac{\sin \left(\pi \cos ^2 x\right)}{x^2}$ is equal to

Which one of the following is the pair of equivalent circuits?