# Thread: Relative max and min

1. ## Relative max and min

I need to find the relative max and min, but I'm having a little trouble finding the derivative. Do I use the log rule then the power rule?

y=(ln3x)^2

2. Originally Posted by hotblonde
I need to find the relative max and min, but I'm having a little trouble finding the derivative. Do I use the log rule then the power rule?

y=(ln3x)^2
Use the chain rule.

Spoiler:
Let $u = \ln (3x) \Rightarrow \frac{du}{dx} = \frac{1}{x}$ and $y = u^2$.

Spoiler:
Then $\frac{dy}{dx} = \frac{dy}{du} \cdot \frac{du}{dx}$.

Spoiler:
Then substitute back that $u = \ln (3x)$.

Spoiler:
Tut tut. You have to do at least some of the work, you know.