# Homework Help: Rate of change derivative?

1. Oct 11, 2012

### Math Sucks

Rate of change.... derivative?

1. The problem statement, all variables and given/known data

the total number of people(in millions) present in a population at a given time is given by the function:

2t(5t+9)^1/2+12

where t represents time (in hours) find the rate in change of the population after 2.5 hours...

2. Relevant equations

3. The attempt at a solution

im so confused do i find the derivative ?

2. Oct 11, 2012

### Dick

Re: Rate of change.... derivate?

Sounds like a good idea to me. The derivative is the rate of change.

3. Oct 11, 2012

### Math Sucks

Re: Rate of change.... derivative?

i got 10t+9..

4. Oct 11, 2012

### Math Sucks

Re: Rate of change.... derivative?

10(2.5)+9.... 34?

5. Oct 11, 2012

### Dick

Re: Rate of change.... derivative?

Now how did you get that? Your expression looks like $2 t \sqrt{5 t + 9}+12$, is that right? Looks like you'll need the product rule and chain rule etc to differentiate it.

Last edited: Oct 11, 2012