Understanding the Derivative of 3ln5x: Solving a Common Integration Dilemma

[Nawz]

Homework Statement

I think it was: 3ln5x

Homework Equations

The Attempt at a Solution

I just took it on a test. My professor said it was 3/x but I don't see how you get that?

When you get the integral of 3/x how do you get the 3ln5x? Where does the 5 go? I don't understand :(

 

[Dick]

It is 3/x if you mean to differentiate 3*ln(5*x). There are a couple of different ways to do this. i) use the chain rule, or ii) use the properties of logs before you differentiate.