Find the instantaneous velocity At a time $t$ seconds after it is thrown up in the air, a tomato is at a height of $f(t) = −4.9t^2 + 25t + 9$ meters.
Find the instantaneous velocity of the tomato at $t = 1.8$.

Hint: You want to calculate the derivative of $f(t)$ and then evaluate the derivative at $t=1.8$, i.e. you want to find $f'(1.8)$.
