Angle Between Two Lines

GRADIENT INTERCEPT FORM

                        The gradient intercept form of the equation of a line is y = mx + c

Example:       Determine the equation of the line whose gradient is -2 and y-intercept is 3..

                                                                        Solution

            Let the equation of the line be y = mx + c, where m = -2 and c = 3

Hence, the equation of the line is y = -2x + 3

Evaluation:    1.         Determine the equation of the line whose gradient is 3 and y-intercept is -4.

                        2.         Find the acute angle between the lines 2y = 3x – 8 and 5y = x + 7.

Conclusion: Teacher summarizes the topic, marks the students’ notes, does correction and allows the students to copy.

Assignment:   1.         Determine the equation of the line whose gradient is 3¼  and y-intercept is -6.

                        2.         Find the acute angle between the lines 2y = – 5x + 8 and y = 3x – 7.

PERIOD 3

Topic:             Equation of a straight line

Sub-topic:      Gradient and one point form and two point form

Duration:       40 minutes

Learning Objectives: By the end of the lesson, students should be able to determine the equation of a line in different forms.

Reference Materials: i. New Further Mathematics for SSS 2 Project 2.

Previous Knowledge: Students can calculate angle between two lines.

Instructional Materials: Graph book.

Content:                                             GRADIENT AND ONE POINT FORM

          Equation of a line through (x, y) with gradient m is y – y₁ = m(x – x₁)

Evaluation:  Find the equation of a line AB which passes through the points (-2, -3) and (-2, -13)

Conclusion: Teacher summarizes the topic, marks the students’ notes, does correction and allows the students to copy.

Assignment: Find the equation of a line AB which passes through the points (-1, 2) and (3, 0)Assignment: New General Mathematics for SSS 2, by M.F Macrae et al. Page 190, Exercise 16d, no 2a, 2c