Define the double factorial of n, denoted , as follows: ={1⋅3⋅5(n−2)⋅nif n is odd 2⋅4⋅6(n−2)⋅nif n is even and (−1)==1. find the radius of convergence for the given power series. ∑n=1[infinity]9n⋅n! ⋅(5n+4)! ⋅(2n)⋅[(n+6)! ]5⋅(4n−4)(8x−2)n