1. ## another calc problem.

This one I forgot to include with my previous question.

A particle moves along a line so that its position at any time t≥0 is given by the function s(t)=t³-8t+1, where s is measured in feet and t is measured in seconds.

Find the average velocity during the first 3 seconds, and at what values of t does the particle change direction?

My answer for the average velocity is 5ft/s, and my answer for the second part is 1.60s and -1.60s.

How close am I?

2. Hello,

My answer for the average velocity is 5ft/s
You forgot to divide by 3.

$=\frac{f(3)-f(0)}{3-0}$

and my answer for the second part is 1.60s and -1.60s.
I find rather 1.63

moreover, time cannot be negative, so you have to keep the positive solution only;