At $$t=0,$$ the function $$f\left( t \right) = {{\sin t} \over t}\,\,$$ has

Divergence of the $$3$$ $$-$$ dimensional radial vector field $$\overrightarrow r $$ is

A box contains $$4$$ white balls and $$3$$ red balls. In succession, two balls are randomly selected and removed from the box. Given that first removed ball is white, the probability that the $$2$$^nd removed ball is red is

For the differential equation $${{{d^2}x} \over {d{t^2}}} + 6{{dx} \over {dt}} + 8x = 0$$ with initial conditions $$x(0)=1$$ and $${\left( {{{dx} \over {dt}}} \right)_{t = 0}}$$ $$=0$$ the solution