X and Y are jointly continuous random variables. The associated joint pdf is: F(x,y) = { C(X"4+y"2) 1

X and Y are jointly continuous random variables. The associated joint pdf is: = { c(xA4+YA2) -1 < x < 1, O Otherwise The associated marginal pdf of Y is: F(x) = {15/16(yA2 + 1/5) 0 Otherwise The variance of X is Var()() = 10/21, and the mean of X is E(X) = O QI. Find the value of c, that makes f(x,y) into a valid pdf