Activity 1.3.2

Consider the function $f$ whose formula is $\displaystyle f(x) = 3 - 2x$.

1. What familiar type of function is $f$? What can you say about the slope of $f$ at every value of $x$?

2. Compute the average rate of change of $f$ on the intervals $[1,4]$, $[3,7]$, and $[5,5+h]$; simplify each result as much as possible. What do you notice about these quantities?

3. Use the limit definition of the derivative to compute the exact instantaneous rate of change of $f$ with respect to $x$ at the value $a = 1$. That is, compute $f'(1)$ using the limit definition. Show your work. Is your result surprising?

4. Without doing any additional computations, what are the values of $f'(2)$, $f'(\pi)$, and $f'(-\sqrt{2})$? Why?