1. Use a coordinate system, place the origin at the intersection. Then the startpoint is S(2,0) and the endpoint is E(0,3).

2. The direction vector of Camerons way is:

3. The vector equation, which describes Camerons way, is:

4. The distance between any point of this line and the origin(= intersection) is calculated by:

5. Calculate the first derivative of d:

6. Now plug in to calculate the rate of change. I've got