Problem #7




Given the m×n array of points whose first coordinates come from the set {1,2,...,m} and whose second coordinates come from the set {1,2,...,n}, what is the total number of lines determined by all pairs of these points? For example when m = 3 and n = 2, the figure below shows that there are 11 lines (3 vertical, 2 horizontal, 4 at a 45 degree angle, and 2 other diagonals).

The solution will be posted shortly.

Back to the Archives


Back to the Math Department Homepage.