# Assignment 3

• For Section 2.1 no. 36, remember another formula to derive the derivative of a function, say $f(x)$, at $x=a$, which is $\lim_{t\to a}\frac{f(x)-f(a)}{x-a}$.
• Some students forgot to explain the meaning of the graph of $P'(t)$ in Section 2.2 no. 12, or forgot to mention the domains of the function and the derivative in Section 2.2 no. 20.