Let XXX and YYY have a joint PDF f(x,y)=2f(x,y) = 2f(x,y)=2 for 0≤y≤x≤10 \le y \le x \le 10≤y≤x≤1. Calculate the conditional expectation E[X∣Y=y]E[X|Y=y]E[X∣Y=y].
1+y2\frac{1+y}{2}21+y
1+y22\frac{1+y^2}{2}21+y2
1−y22\frac{1-y^2}{2}21−y2
1+yy\frac{1+y}{y}y1+y