Fraction Differences

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Fraction Differences

First Sequence

To begin with I looked at the first sequence of fractions to discover

the formula that explained it. As all the numerators were 1 I looked

at the denominators. As these all increased by 1 every time, I

figured that the formula was simply [IMAGE] as the denominators

corresponded to the implied first line as shown in this table below:

nth number

1

2

3

4

5

6

7

8

Denominators

1

2

3

4

5

6

7

8

I shall call this Formula 1 (F1) for easy reference.

Second Sequence

[IMAGE] [IMAGE] [IMAGE] [IMAGE] [IMAGE]

Again I decided to discount the numerator as it was 1, and I decided

to concentrate on the differences between the denominators rather than

the ‘fractions’. So I am looking for a formula that will explain the

sequence: 2, 6, 12, 20, 30.

First of all though I decided to extend the sequence in order to have

a broader range to work with. I used a calculator to work out the

following denominators finding the difference between [IMAGE] and

[IMAGE], [IMAGE] and [IMAGE] all the way up to [IMAGE]

I set the differences out in a table to try to find the pattern:

nth number

1

2

3

4

5

6

7

8

9

Sequence

2

6

12

20

30

42

56

72

90

First Difference

4

6

8

10

12

14

16

18

Second Difference

2

2

2

2

2

2

2

2

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