Would like help with this question Question:y = 4ln3x, find dy/dx 2. Relevant equations 1. I used the chain rule: y=4ln u and u =3x dy/du=4/u THIS IS MY PROBLEM There is no number between the ln and u, eg. ln4u, so WHY do you use d/dx ln(ax+b)=a/(ax+b)? 3. The attempt at a solution y=4ln u and u =3x dy/du=4/u du/dx=3 dy/dx=12/3x=4x.