Is my illustration correct? How do I start this problem? What formula do I need to use? Please consider to answer this problem because I don’t know how to start .
Suppose the corner is at $\displaystyle (0,0)$ and the end points of the log $\displaystyle P,Q$ are in the lines $\displaystyle y=8$ and $\displaystyle x=4$. Consider the family of lines $\displaystyle y=mx$ passing through $\displaystyle (0,0)$ . Find the points $\displaystyle P,Q$ and the minimum of $\displaystyle f(m)=d(P,Q)$.