# Finding Rate of Change

1. Sep 3, 2014

### RunnerDP

1. The problem statement, all variables and given/known data
Hi everyone, I am new to calculus. I was recently assigned some homework and am having a difficult time with it. Please help me out. Thank you!

A bicyclist is riding on a path modeled by the function f(x) = 0.04(8x - x^2), where x and f(x) are measured in miles. Find the rate of elevation when x = 2.

2. Relevant equations

N/A

3. The attempt at a solution

My only attempt was utilizing an equation my teacher gave me. However, the answer I got and the one on CalcChat are substantially different.

Thank you so much.

2. Sep 3, 2014

### Ray Vickson

Is x the horizontal distance and f(x) the altitude?

You need to show us your work. We cannot possibly comment until we see what you have done already. Maybe you are right and CalcChat is wrong, or maybe the opposite is true---who knows, since you do not include either answer?

3. Sep 3, 2014

### HallsofIvy

Staff Emeritus
In particular, what was this equation your teacher gave you? Do you know how to find the derivative of f(x)?