Originally Posted by

**pocketasian** I am given a position equation

$\displaystyle s(t)=2t^3-24t^2+90t+7$ for t is greater than or equal to 0. I am asked to find the values of t where the speed is increasing.

If I'm correct, speed is the absolute value of velocity, which is the derivative of position. I got:

$\displaystyle y=$|$\displaystyle 6t^2-48t+90$|

(not sure how to input absolute value symbol)

How do I know where the speed is increasing without plugging it into the calculator? To find where velocity increases, I found the zeros and then used a sign line, but I don't think that works for speed...or does it?