1. Onto, one-to-one, bijection Consider the function: f: NU {0} NU {0} where f is defined as: x+1 if x is even x+1 f(x) = x-1 if x is odd 1. Is f is one-to-one? If yes prove it, otherwise provide a counter example. 2. Is f is onto? If yes prove it, otherwise provide a counter example. 3. Is f is bijection? If so, find f-1, inverse of f.