The random variables $X$ and $Y$ have a joint density function given by; $$f(x,y)= \begin{cases} Kxy,\quad &0\leq x\leq 1,\; 0\leq y\leq 1,\\ 0,&\text{otherwise}. \end{cases} $$
Determine $K$ and find the density functions of the random variables $Z = \max(X,Y)$ and $T = \min(X, Y )$.