(Redirected from 4.2b Junzhe Geng ECE302Fall2008sanghavi)
Use the binomial theorem to expand the expression (x+y)^n+(x-Y)^n you will find out that only the terms with even n remains. Then you relate this model to the problem by substituting x,y with p, 1-p and you will find out that the right hand side(the expanded terms) is 2 times P(X is even), so you can solve it.
