Question 1 (10 pts)
The joint probability density function (PDF) of the random variables X and Y, is given
as;
$$f_{X,Y}(x,y) = \begin{cases}
ke^{-(ax+by)}, & x > 0, y > 0, \\
0, & \text{otherwise}.
\end{cases}$$
where a and b are positive constants and k is a constant.
a) Find the value of k.
b) Determine whether or not X and Y are independent.