Jointly continuous PDF In order for a function f(x,y)to be a joint density it must satisfy f(x,y)≥0 fr(x.y)dx dy =1 6Jointly continuous PDF • In order for a function 𝑓(𝑥, 𝑦) to be a joint density it must satisfy 𝑓(𝑥, 𝑦) ≥ 0 න −∞ ∞ න −∞ ∞ 𝑓𝑋,𝑌 𝑥, 𝑦 𝑑𝑥 𝑑𝑦 = 1 6