The maximum value of $$f\left( x \right) = 2{x^3} - 9{x^2} + 12x - 3$$
in the interval $$\,0 \le x \le 3$$ is __________.

If $$z=xy$$ $$ln(xy),$$ then

The maximum value of the function $$\,f\left( x \right) = \ln \left( {1 + x} \right) - x$$ (where $$x > - 1$$ ) occurs at $$x=$$________.

A fair coin is tossed repeatedly till both head and tail appear at least once. The average number of tosses required is ________.