How to Calculate Total Toothpicks and Squares in Any Figure of the Sequence?

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Discussion Overview

The discussion revolves around finding a formula to calculate the total number of toothpicks and squares in a sequence of figures based on their figure number. Participants explore patterns in the increases of toothpicks and squares across the figures, aiming to derive a general formula without resorting to listing each figure sequentially.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • Some participants express frustration with the need to list figures to determine the number of toothpicks and squares.
  • One participant suggests counting the additional toothpicks needed to transition from one figure to the next to identify a pattern.
  • A participant presents a table showing the number of toothpicks and squares for the first five figures, along with their increases, indicating a structured approach to identifying patterns.
  • Another participant asks about the second difference in the increases of toothpicks, hinting at a deeper mathematical exploration of the sequence.
  • There is a suggestion to use the concept of arithmetic progression to derive a formula for the number of toothpicks based on the figure number.

Areas of Agreement / Disagreement

Participants generally agree that there are identifiable patterns in the increases of toothpicks and squares, but there is no consensus on a definitive formula yet. The discussion remains exploratory with multiple approaches being considered.

Contextual Notes

Participants have not yet resolved the mathematical steps needed to derive a formula, and there are dependencies on the definitions of the sequences being discussed.

marsman
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Please help! I need to be able to find the number of total toothpicks used in any given figure in this sequence, in addition to total squares in any figure, using the figure number.View attachment 1592
The only way I can figure this out is by listing them all out one by one, which is TERRIBLE :(
Thank you so much in advance!
 

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marsman said:
Please help! I need to be able to find the number of total toothpicks used in any given figure in this sequence, in addition to total squares in any figure, using the figure number.View attachment 1592
The only way I can figure this out is by listing them all out one by one, which is TERRIBLE :(
Thank you so much in advance!
Suggestion: In the six figures, count how many toothpicks you have to add to each figure in order to get the next one. Can you see a pattern there?
 
Opalg said:
Suggestion: In the six figures, count how many toothpicks you have to add to each figure in order to get the next one. Can you see a pattern there?

Yeah I'm up to my neck in patterns; I made a table and everything.
[table="width: 500, class: grid"]
[tr][td]Figure Number[/td]
[td]1[/td]
[td]2[/td]
[td]3[/td]
[td]4[/td]
[td]5[/td]
[/tr]
[tr][td]Number of Toothpicks[/td]
[td]4[/td]
[td]10[/td]
[td]18[/td]
[td]28[/td]
[td]40[/td]
[/tr]
[tr][td]Increase in Toothpicks[/td]
[td]+4[/td]
[td]+6[/td]
[td]+8[/td]
[td]+10[/td]
[td]+12[/td]
[/tr]
[tr][td]Number of Squares[/td]
[td]1[/td]
[td]3[/td]
[td]6[/td]
[td]10[/td]
[td]15[/td]
[/tr]
[tr][td]Increase in Squares[/td]
[td]+1[/td]
[td]+2[/td]
[td]+3[/td]
[td]+4[/td]
[td]+5[/td]
[/tr]
[/table]
My problem is that I can't get from the patterns to creating a formula that would work for any figure number without listing them all out consecutively
 
I see you have found that the difference in the number of toothpicks per iteration (where you state the increase in toothpicks) are the sequence of even numbers, beginning with 4. What is the second difference, that is, the difference of the differences. How much does the increase increase each time?
 
marsman said:
Yeah I'm up to my neck in patterns; I made a table and everything.
[TABLE="class: grid, width: 500"]
[TR]
[TD]Figure Number[/TD]
[TD]1[/TD]
[TD]2[/TD]
[TD]3[/TD]
[TD]4[/TD]
[TD]5[/TD]
[/TR]
[TR]
[TD]Number of Toothpicks[/TD]
[TD]4[/TD]
[TD]10[/TD]
[TD]18[/TD]
[TD]28[/TD]
[TD]40[/TD]
[/TR]
[TR]
[TD]Increase in Toothpicks[/TD]
[TD]+4[/TD]
[TD]+6[/TD]
[TD]+8[/TD]
[TD]+10[/TD]
[TD]+12[/TD]
[/TR]
[TR]
[TD]Number of Squares[/TD]
[TD]1[/TD]
[TD]3[/TD]
[TD]6[/TD]
[TD]10[/TD]
[TD]15[/TD]
[/TR]
[TR]
[TD]Increase in Squares[/TD]
[TD]+1[/TD]
[TD]+2[/TD]
[TD]+3[/TD]
[TD]+4[/TD]
[TD]+5[/TD]
[/TR]
[/TABLE]
My problem is that I can't get from the patterns to creating a formula that would work for any figure number without listing them all out consecutively
Let $x_n$ be the number of toothpicks in Fig. $n$. Your table shows that $x_1=4$, $x_2=4+6$, $x_3=4+6+8$, $x_4=4+6+8+10$, $\ldots$. So what is the formula for $x_n$?

[sp]Hints: arithmetic progression, $n$ terms, first term $4$, common difference $2$.[/sp]
 

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