# Domain

The domain is the set of values on which a function operates. For instance, the domain of the square root function is usually taken to be the non-negative real numbers, while the domain of the function $f(x)=\dfrac{1}{x}$ is usually taken to be all real numbers except for $0$.

We can also specify different domains for these functions, such as defining a function $g(x)=\dfrac{1}{x}$ on all positive real numbers, or on all real numbers between $2$ and $10$, or on all non-zero integers.