Let (X,Y)(X, Y)(X,Y) have joint PDF f(x,y)=2f(x, y) = 2f(x,y)=2 for 0≤x≤y≤10 \le x \le y \le 10≤x≤y≤1. What is the marginal PDF of XXX?
fX(x)=2(1−x)f_X(x) = 2(1-x)fX(x)=2(1−x)
fX(x)=2xf_X(x) = 2xfX(x)=2x
fX(x)=1−xf_X(x) = 1-xfX(x)=1−x
fX(x)=2f_X(x) = 2fX(x)=2