a) Let S= {(-2,4),(-1,1),(0,0),(1,1),(2,4)} with each point equally likely. Let X denote the first cooridinate , Y the second. Show X,Y are independent random variables but Cov(X,Y)=0
b) If X and Y have the joint probability distribution function fx,y(x,y)= ((x+2y)/2^2), for (x,y)= {(1,1),(1,3),(2,1),(2,3)}. and 0 elsewhere. Find the Cov(X,Y) and e(X,Y).