please help with question attached

(10 points) A function f : R2 > R is called a probability density function on D C R2 if (i) f(ac,y) Z 0 for all (33,31) 6 D and (ii) ff f(a:,y)dA =1. D k(1$2 y2) x2+y2 $1 0 2:2 + y2 > 1 ability density function? Note that D = {(11:41) 6 1R2 : x2 + y2 S 1}, the closed unit disk in R2. (1)) If ay) = { value of k? (a) For what constant k: is the function f (3:, y) = { a prob- k. a:2_._y2s,r2 is a probability density function what must be the O 9:2 + y2 > r2