5. (5,6) Hint: Find the symmetric point $A^{\prime}(0,1)$ of $A$ with respect to the line. When $A^{\prime} 、 B 、 P$ are collinear, the difference in distances is maximized.
5. On the line $2 x-y-4=0$, there is a point $P$, which has the maximum difference in distance to two fixed points $A(4,-1), B(3,4)$. Then the coordinates of $P$ are $\qquad$