Is the Circle Division Math for the Stator Correct?

  • Thread starter Thread starter MacLaddy
  • Start date Start date
  • Tags Tags
    Circle Stator
Click For Summary
SUMMARY

The forum discussion centers on verifying the mathematical approach for dividing a circle into nine equal parts, as presented on the website http://www.otherpower.com/statormold.shtml. The user questions the use of \sin20\deg in the calculations, suggesting that \sin40\deg should be utilized instead. They propose using the formula c = r√(2 - 2cos40) to determine the chord length, which aligns with their findings. The discussion highlights the importance of accurate trigonometric applications in geometry.

PREREQUISITES
  • Understanding of basic trigonometric functions, specifically sine and cosine.
  • Familiarity with circle geometry and chord calculations.
  • Knowledge of radians and degrees in mathematical contexts.
  • Ability to apply formulas for dividing circles into equal segments.
NEXT STEPS
  • Research the derivation of the formula for chord length in circles.
  • Learn about the properties of sine and cosine functions in trigonometry.
  • Explore advanced circle division techniques for various applications.
  • Study the implications of angle measurement in geometric calculations.
USEFUL FOR

This discussion is beneficial for mathematicians, engineering students, and hobbyists involved in projects requiring precise geometric calculations, particularly in the context of circle division and trigonometry.

MacLaddy
Gold Member
Messages
290
Reaction score
11
Not a homework question, I was just hoping someone could assist me with understanding some math. Actually, more accurately, I was wondering if someone could double check the math on the following website.

http://www.otherpower.com/statormold.shtml

If you scroll down you will see some explanations on how to accurately divide the circle into nine equal parts, but I believe he is doing it incorrectly. See where the "Sides, Angles, and Sines" paper is shown. Seems odd that he would be using the [tex]\sin20\deg[/tex] when it is [tex]40\deg[/tex].

Wouldn't you just do the following

[tex]\frac{\pi12}{9}~=~4.188...[/tex]

Thanks for any input you can offer. I have been considering taking up this project, but if the math is wrong I may not...
 
Last edited by a moderator:
Engineering news on Phys.org
Well, I digress. I realized that I needed to figure out the "chord" for the angle, as it will not follow the arc. So I used the formula [tex]c~=~r\sqrt{2-2cos40}[/tex]. That gave the same answer that he was coming up with by just multiplying [tex]\sin20~by~12.[/tex]

I apologize if I posted this in the wrong section, it just seemed appropriate here due to the subject matter.

Apparently I'm missing something in my trig knowledge.
 
Last edited:

Similar threads

High School Why are light waves depicted as lines, circles, and sinusoids?
  • · Replies 18 ·
Replies
18
Views
4K
High School Hopf fibration, Bloch sphere and quantum rotations - interactive site
  • · Replies 1 ·
Replies
1
Views
3K
My Grade 11 Math mark is eating me alive. What do I do?
  • · Replies 21 ·
Replies
21
Views
178K
Arc length of intersecting circles
  • · Replies 3 ·
Replies
3
Views
3K
Studying Interested in Astronomy as a Freshman
  • · Replies 20 ·
Replies
20
Views
2K
Equilibrium Position of a Hanging Candy Cane
  • · Replies 17 ·
Replies
17
Views
2K
MHB Analogy Between Long Division and Polynomial Long Division
  • · Replies 5 ·
Replies
5
Views
4K
Challenge Math Challenge - December 2020
  • · Replies 60 ·
3
Replies
60
Views
13K
Challenge Math Challenge - December 2019
  • · Replies 48 ·
2
Replies
48
Views
12K
Plot xy, coords to create a circle with centrepoint and radius
  • · Replies 2 ·
Replies
2
Views
7K