Mathematics for IGCSE & O level - Coordinate Geometry (Section 3 - No. 38)
What is the gradient of a line perpendicular to a line with equation y = -2/5x + 3?
2/5
-2/5
5/2
-5/2
คำอธิบาย
Perpendicular lines have negative reciprocal gradients. The negative reciprocal of -2/5 is 5/2.