So I have been given the definition of a "closed form function" that is a set of functions built inductively (mapping from and to the complex) starting with the fact that the constant functions $0(x)=0$ and $1(x)=1$ for all $x$ belong to our set, and then the rest is found inductively by saying that the set is closed under addition, multiplication, the negative of a function belongs to our set. Our set is also closed under exponentiation and if our functions isn't equal to $0$, an inverse exists and our set is closed under taking logarithm (principal branch).
I have been given the task to show that the composition of any two "closed form functions" is still a closed form function. Any hints on how I could go about proving this.