Question 3 - Normal form - Chapter 9 Class 11 Straight Lines
Last updated at April 16, 2024 by Teachoo
Normal form
Last updated at April 16, 2024 by Teachoo
Example 11 Find the equation of the line whose perpendicular distance from the origin is 4 units and the angle which the normal makes with positive direction of x-axis is 15 . We need to find equation of line Perpendicular distance of AB from origin is 4 units & angle which the normal makes with (+)ve direction of x-axis is 15 By Normal from Equation of line is x cos + y sin = p where, p = normal distance from the origin & = angle which makes by the normal with positive x-axis Here p = 4 & = 15 Putting values x cos + y sin = p x cos 15 + y sin 15 = 4 x (( 3 + 1)/(2 2)) + y (( 3 1)/(2 2)) = 4 ( ( 3 + 1) + ( 3 1))/(2 2) = 4 x( 3 + 1) + y( 3 1) = 4 2 2 ( 3 + 1)x + ( 3 1)y = 8 2 Which Is the required equation