Recursion Haskell ghci

Define a recursive function of type isEven :: Integer -> Bool that returns true if the input integer is even, and false otherwise (dont use the mod operator!) If you are stuck, work the steps of solving a problem recursively by divide-and-conquer (from Lecture 2). Initially ignore negative numbers but consider them once you have it solved for positive numbers.

Addendum: of course, in isEven, we could have used the mod operator instead and written

isEven n = mod n 2 == 0

A further note on infix notation A last thing to learn: in Haskell, any function can be made into an infix operator by wrapping it in backquotes. For example, we could write isEven equivalently as

isEven n = n mod 2 == 0