### Home > APCALC > Chapter 7 > Lesson 7.1.3 > Problem7-31

7-31.

If Hoi Yin’s hair is of length $h$, and $t$ represent time, explain what $\frac { d h } { d t }$ represents. Is it positive or negative?

The derivative represents instantaneous slope (growth). Is the length of Hoi Yin's hair growing at a positive or negative rate?