題組內容

5. (26%) Let X and Y be jointly distributed random variables with joint PDF $$f_{X,Y}(x,y) = \begin{cases} k, & 0 \le x \le y \le 2; \\ 0, & \text{otherwise} \end{cases}$$ where k is a constant.

(c) Find the marginal expectation E[X]. (6%)