Formulas

Question 1

what is the distance formula?

Answer 1

D = ( x2 - x1) 2 + (y2 - y1)2

All square rooted

Question 2

How do you know if points are collinear?

Answer 2

If 3 or more points lie on a straight line, they are said to be collinear.
If MAB = MBC points are collinear and therefore lie on a straight line

Question 3

How to work out the Median

Answer 3

• Midpoint

X1+x2. Y1 +y2
2. 2
• find the gradient using the midpoint
• equation

Y-b=m(x-a) with (a,b) the midpoint

Question 4

How do you work out the altitude?

Answer 4

• gradient
• m1 x m2 = -1
• y-b=m(x-a)

Question 5

How do you work out the perpendicular bisector?

Answer 5

• midpoint
• gradient
• m1 x m2
• equation (midpoint as (a,b))

Question 6

Formula for recurrence relations

Answer 6

un+1 = aun + b

Question 7

What will “a” need to be for a limit to exist?

Answer 7

-1<a>1</a>

Question 8

Formula for working out the limit

Answer 8

L = b

1-a

Question 9

What is AB (vectors) equal to?

Answer 9

b-a

Question 10

The vector -1
6
-3
Can be written in terms of i, j and k

Answer 10

-i + 6j - 3k

Question 11

How do you know if a and b are perpendicular

Answer 11

If a.b = 0

Question 12

What is the scalar product?

Answer 12

a.b = |a| |b| cos0

Question 13

What are the exact values of sinx?

Answer 13

0 = 0

30 = 1/2

45 = 1/root2

60 = root3/2

90 = 1