If a ball is thrown in the air with a velocity $34$ ft/s, its height in feet $t$ seconds later is given by
$$ y = 34 t − 16 t^2 .$$
Find the average velocity for the time period beginning when $t = 2$ and lasting $0.5$ second, $0.1$ second, $0.05$ second, $0.01$ second and estimate the instantaneous velocity when $t = 2$.
I tried to solve by doing the following:
but I was told that answer is incorrect.
What did I do wrong?