Exercise 12

Suppose that an object is tossed directly upward in the air in such a way that the elevation of the object (measured in ft) is given by the function $\fe{s}{t}=150+60t-16t^2$ where $t$ is the amount of time that has passed since the object was tossed (measure in seconds).

Use the difference quotient to determine the average velocity of the object over the interval $\cinterval{4}{4.2}$ and then verify the value by calculating $\frac{\fe{s}{4.2}-\fe{s}{4}}{4.2-4}$.