Solution : Angle between lines with slope m1 & m2 is given by tan θ = |( m2-m1 )/ ( 1 + m1m2 )| Here θ = π / 4 , m1 = ½ , we need to find m2
Putting these values in the equation , we get tan π / 4 = |( m2-1 / 2 )/ ( 1 + ½ * m2 )| or 1 = |( m2-1 / 2 )/ ( 1 + ½ * m2 )| Solving this we get m2 = 3 or -1 / 3 Collinearity of 3 points
If two lines having same slope pass through a common point , then two lines will coincide .
Hence , if A , B and C are Collinear if and only if slope of AB = slope of BC .
Various forms of Equation of line o o o
Horizontal and vertical lines Point-slope form Two-point form