In: Math
A 4 mile by 4 mile grid is shown in figure below: Let A and B be two points at a distance miles, then if x be the number of horizontal grids and y be the number of vertical grids, then the total number of grids between A and B is
So, the distance between the two grids A and B is:
Differentiating (i) with respect to x, we get
Therefore,
Therefore, the maximum number of signs that can be place (Excluding A and B) = 3