Let $f(x) = \displaystyle \frac{1}{x^{6}}$ and $g(x)= x.$ Find $f \circ g$ and $g \circ f$, and their respective domains.

---

1. $(f \circ g)(x) =$

2. What is the domain of $f \circ g$ ?
Answer (in interval notation):

3. $(g \circ f)(x) =$

4. What is the domain of $g \circ f$ ?
Answer (in interval notation):

---