We have studied combination of algebra and geometry in two-dimensional coordinate geometry. Let us recollect the following Important Formula of Straight Lines in Co-ordinate Geometry, we learnt earlier.
Straight Lines – Important Formula
Slope of a Line
Slope of line passing through 2 given points
P(x1,y1) and Q(x2, y2) are two points on non-vertical line l whose inclination is 𝜃 (F-2). So, x1≠x2, (otherwise the line will become perpendicular to x-axis and its slope would be undefined). The inclination of the line l may be acute or obtuse. We would take up take both cases.
Draw perpendicular QR to x-axis and PM perpendicular to RQ.