I was wondering if anyone could help me with a question I was trying to work through today in our A-level math class.(adsbygoogle = window.adsbygoogle || []).push({});

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

a. Sketch the graph of y= ln(3x)

b. The normal to the curve at Point Q, with x coordinate q, passes through the origin. Find the equation of the normal and the value of q

2. Relevant equations

I donâ€™t know which to use

3. The attempt at a solution

Part a was not too difficult and I was able to do that

However I have no idea how to tackle part b. I have only been able to express the gradient of the normal as-q, but cannot solve it. I think [but am not sure] that I can get to the equation

ln3q + q^2 = 0

but I cannot solve this.

I would be very grateful for some help.

Thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Finding normal to ln curve

**Physics Forums | Science Articles, Homework Help, Discussion**