# Math Help - Functions help

1. ## Functions help

A soccer ball is kicked into the air so that its height, h in metres, after t seconds is modelled by the function h(t)= -4.9t(squared)+12t+0.5

h=0.05

Estimate the instantaneous rate of change of the height of the ball after 2 s.

I got -7.6, but I'm not sure if that's right, any help would be appreciated

2. ## Re: Functions help

You are correct.

Thank you!

4. ## Re: Functions help

Originally Posted by lucida
A soccer ball is kicked into the air so that its height, h in metres, after t seconds is modelled by the function h(t)= -4.9t(squared)+12t+0.5

h=0.05

Estimate the instantaneous rate of change of the height of the ball after 2 s.

I got -7.6, but I'm not sure if that's right, any help would be appreciated
It's easier to check for mistakes if you show your working. Otherwise, we have to spend time getting an answer and comparing it against yours.

Calculating $\frac{h(2.01) - h(2)}{0.01}$ for example will give a close answer.