To investigate and discover an equation, numerically and algebraically.

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Maths coursework: January 2001.

Aim: To investigate and discover an equation, numerically and algebraically.

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Method:

We experimented with different grid sizes, including 9 and 7. We found out the total of the numbers inside the t-shape.

(Red) T = 1+2+3+11+10 = 37

If I move the T across I can investigate the relationship by comparing the various t-totals.

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T= total

G= grid size

N= t number (e.g.) 20

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T

Difference

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37

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5

To try and find a formula for the red T, I used the difference, 5 and multiplied it by the N number. 5 x 20 = 100. However the number we need is T: 37. So to get 37 from 100 I need to subtract 63. So, we would then be able to write the formula as:

T= 5N-63

5x20=100

100-63 = 37. (T)

I now know this works for the Red T but I must prove that it works for both the blue and the yellow T-shape.

Formula: T=5N-63

When N=21

5x 21 = 105

105-63= 42

So the formula has worked for the upright t again but for a different set of numbers. I moved the T along one square again this made "yellow T". I'll try the formula on this one and prove the formula is right.

Formula: T=5N-63

When N=22

5x22=110

10-63 = 47

So once more the formula has worked. If we try and put this algebraically it will look something like this.

N-19

N-18

N-17

N-9

N

So, T = N+(N-9)+(N-18)+(N-17)+(N-19)

=5N-63 63= 7x9

9 = G Algebraic Formula for upright T = 5N-7G

G is changed to seven:

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Difference

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Does the same formula work when the grid size is reduced to seven.
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When N= 16

T = 16+9+2+1+3

= 31

T= 5N-7G

5N = 80

7x7 = 49

80

-49

31

7x7 = 49

Formula: T= 5N-7G

The formula is the same -Algebraically- when grid size is seven, however not numerically.

If you move the shape over one square N =17

T= 17+10+3+4+2= 36

5x17= 85

85-49= 36 T=5N-7G

Just to prove it I'll move the T over one again and test the formula.

N= 18 T= 18+11+4+3+5= ...

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