A soccor ball is kicked into the air. The polynomial function f(t) = -4.9^2 +16t + 1, where the f(t) represents the height in metres at t seconds models this scenario.

Determine the instantaneous rate of change of height at 1 second, 2 seconds and 3 seconds.

Im thinking I use this:

f ' (1) = lim_____f(1 + h) - f(1)

______ h→0______h

and so forth for 2 seconds, and 3 seconds..

But I got 87.71 m/s for 1 second - doesn't seem right?

Help lol thanks in advance