If $\mathrm{f}(x)=\frac{\log x}{x}(x>0)$, then it is increasing in

The maximum value of $\frac{\log x}{x}$ is

If the curves $y^2=6 x, 9 x^2+\mathrm{b} y^2=16$ intersect each other at right angles, then the value of $b$ is

If Mean value theorem holds for the function $\mathrm{f}(x)=(x-1)(x-2)(x-3), x \in[0,4]$ then the values of $c$ as per the theorem are