The joint probability density function of two random variables $\mathrm{x}$ and $\mathrm{y}$ is given by $\mathrm{f}(\mathrm{x},\mathrm{y})=\left\{\begin{array}{ll}\mathrm{k}(\mathrm{x}+2\mathrm{y});& 0\mathrm{x}1,0\mathrm{y}2\\ 0;& \mathrm{elsewhere}\end{array}\right.$. Find the marginal density function of $\mathrm{x}$ and $\mathrm{y}$.