Mathematics for IGCSE & O level - Coordinate Geometry (Section 1 - No. 14)
What is the gradient of a line perpendicular to a line with a gradient of 1/2?
-2
2
1/2
-1/2
解释
The gradient of a perpendicular line is the negative reciprocal. So, if the gradient is 1/2, the perpendicular gradient is -2.