Let $a_{1}, a_{2}, \ldots, a_{n}$ be fixed real numbers and define a function
$$
f(x)=\left(x-a_{1}\right)\left(x-a_{2}\right) \ldots\left(x-a_{n}\right) .
$$
What is $\lim _{x \rightarrow a_{1}} f(x) ?$ For some $a \neq a_{1}, a_{2}, \ldots, a_{n}$, compute $\lim _{x \rightarrow a} f(x)$.