Warden 2006

To find the gradient of lines perpendicular to each other.

Warden 2006

Finding the Midpoint

1 2 3

6

9

5

8

4

7

Starter

(We’re going to use this later)

Warden 2006

These lines are perpendicular

Warden 2006

PERPENDICULAR PERPENDICULAR MEANSMEANS

AT RIGHT ANGLESAT RIGHT ANGLES

Warden 2006

What is each gradient?

21

Gradient = ½

2

1

Gradient = -2

Warden 2006

What is each gradient?

3

1

Gradient = 3

31

Gradient = -1/3

Warden 2006

THE GRADIENT OF A THE GRADIENT OF A PERPENDICULAR LINE IS THEPERPENDICULAR LINE IS THE

NEGATIVE RECIPROCALNEGATIVE RECIPROCALOF THE OTHEROF THE OTHER

Warden 2006

What is the gradient of the lines perpendicular to these?

y = 2x + 1

y = 3x + 2

y = 2 + 4x

y + 2x = 2

2y = 3x - 2

5y + 2x = 3

m = 2

m = 3

m = 4

m = -2

m = 3/2

m = -2/5

-1/m= -1/2

-1/m= -1/4

-1/m= -1/3

-1/m= 1/2

-1/m= -2/3

-1/m= 5/2

Warden 2006

Write down an equation of a line perpendicular to these:

y = 2x + 1

y = 3x + 2

y = 2 + 4x

y + 2x = 2

2y = 3x - 2

5y + 2x = 3

Warden 2006

THE PRODUCT OF GRADIENTS OFTHE PRODUCT OF GRADIENTS OFPERPENDICULAR LINES IS EQUAL PERPENDICULAR LINES IS EQUAL

TO -1TO -1

Exercise 5E Question 1

Warden 2006

Two points A(1,2) and B(-3,6) are joined to make the line AB.

Find the equation of the perpendicular bisector of AB