I'm confused and I'd like assistance in trying to better understand how to solve this type of problem.

The Ratio Test is commonly used with series that contain factorials, and factorials are also going to become more common in the next few sections. Problems 31 -40 ask you to simplify factorial expressions in order to get ready for that usage. (Definitions: 0! = 1, 1! = 1, 2! = 1.2 =2, 3! = 1.2-3 =6, 4! =24, and, in general, n! = 1.2-3. ... (n-1)'n ) 2(n!) 2 36. Show that (2n)! = (n+1).(n+2)....'(2n)