# Homework Help: If P(x) = g^2(x), then P'(3) = ?

1. Feb 1, 2010

### Knight226

1. The problem statement, all variables and given/known data
If P(x) = g^2(x), then P'(3) =

2. Relevant equations

3. The attempt at a solution
I am not quite sure what g^2(x) means...
But my assumption is do the derivative of g^2(x), so it becomes 2g(x), then put the 3 in for x?
so the final answer will be 2g(3) ?
It looks weird to me, so I am not sure if I am doing it correctly or not.

2. Feb 1, 2010

### sutupidmath

Almost! you need to apply chain rule!

3. Feb 1, 2010

### Staff: Mentor

Also, your inclination that g2(x) = g(x)*g(x) is correct.

4. Feb 1, 2010

### Knight226

To sutupidmath,
Thank you!
So it should be 2g(x)g'(x), thus the final answer for that question would be P'(3) = 2g(3)g'(3).

To Mark44
I got confused a little there because I thought the final answer was different from 2g(x) (which was the wrong answer anyways). Now I redid the problem using product rule instead for g(x)g(x), and my derivative turned out to be g'(x)g(x) + g(x)g'(x), which is the same as 2g(x)g'(x) anyways :D

Thank you so much to both of you.