Hi, i was wondering if someone can help me understand about this problem.

Prove that a function F: R x R --> R satisfy any two of the properties

a)VxVy[F(x,y)=F(y,x)]

b)VxVy[F(x,y)=F(-x,-y)

c)VxVy[(F(x,y)=F(-y,-x)]

must also satisfy the third.

(VxVy stands for all x and for all y)