2. You are mixing and on the RHS of some of the function definitions. There is no requirement for ever to appear on the right in fact it appears undefined leaving us to assume what it means. You also leave us to assume what you want to mean.
3. You also do not make it clear if you intend three functions or in some obscure way you expect the reader to abstract a single function from the apparent three definitions.
4. What is the horizontal brace doing?
5. What you have posted is in fact not a question at all (it does not contain a statement equivalent to something like find, show, prove, demonstrate etc)
6. Probably not important but I asked "do you know ... how to solve this?" You only answer that you "have the answer" not that you know how to solve it. But I will let that go and just assume that you do not see the distinction.