Given f(x,y)=8xyf(x, y) = 8xyf(x,y)=8xy for 0≤y≤x≤10 \le y \le x \le 10≤y≤x≤1. What is the marginal PDF fX(x)f_X(x)fX(x)?
4x34x^34x3
2x22x^22x2
4x4x4x
8x8x8x