WAEC Mathematics 2014 Paper

Concept:The gradient of a line measures its steepness. When the $x$-coordinates of two points are equal, the line is vertical and its gradient is undefined.Explanation:Let the two points be $(x_1, y_1) = (2, -3)$ and $(x_2, y_2) = (2, 5)$.Use the gradient formula: $m = \frac{y_2 - y_1}{x_2 - x_1}$.Substitute the values: $m = \frac{5 - (-3)}{2 - 2}$.Simplify: $m = \frac{5 + 3}{0} = \frac{8}{0}$.Division by zero is not defined in mathematics.Therefore, the gradient of the line joining these points is undefined.Answer:D. undefined