Find the angle between the x-axis and the line joining the points (3,

1.	Find the angle between the x-axis and the line joining the points (3, -1) and (4, -2)
Answer» The given points are A(3, -1) and B = (4, -2) Slope of AB = (-2 - (-1))/(4 - 3) = - 1/1 = - 1 Let θ be the angle made by the line AB with the positive x-axis then slope of AB = tan θ … (2) ∴ From (1) and (2), we have tan θ = -1 = – tan 45° = tan (180°-45°) = tan (135°) = θ =135° AB makes an angle of 135° with positive direction of x-axis

Find the angle between the x-axis and the line joining the points (3, -1) and (4, -2)

Answer»

The given points are A(3, -1) and B = (4, -2)

Slope of AB = (-2 - (-1))/(4 - 3) = - 1/1 = - 1

Let θ be the angle made by the line AB with the positive x-axis then slope of

AB = tan θ … (2)

∴ From (1) and (2), we have

tan θ = -1 = – tan 45°

= tan (180°-45°)

= tan (135°)

= θ =135°

AB makes an angle of 135° with positive direction of x-axis