Can Pi be Constructed on a Number Line Using Non-Traditional Tools?

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Discussion Overview

The discussion revolves around the possibility of constructing the irrational number pi on a number line using non-traditional tools, including compass and straightedge methods. Participants explore both theoretical and practical aspects of this topic, touching on numerical algorithms and geometric constructions.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant describes a method for plotting irrational numbers like pi using geometric constructions based on the Pythagorean theorem.
  • Another participant argues that pi, being transcendental, cannot be constructed with traditional tools, but a circle with a unit diameter can represent pi through its circumference.
  • Some participants engage in a meta-discussion about the nature of a number line and the meaning of "constructing" a length corresponding to pi.
  • There is a request for clarification on the Newton-Raphson method and Taylor series, with a suggestion that these methods are covered in basic calculus courses.
  • One participant asserts that pi cannot be constructed with a ruler and compass but can be represented using other tools.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of constructing pi on a number line, with some asserting it is impossible with traditional tools, while others suggest alternative methods may exist. The discussion remains unresolved regarding the methods and definitions involved.

Contextual Notes

There are limitations in the discussion regarding the definitions of construction and the assumptions about the tools allowed. The mathematical steps involved in the proposed methods are not fully explored or resolved.

vaishakh
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how to plot the irrational number pi on a number line. i know the procedure for square roots of different non-perfecr square number. it is by drawing a perpendicular at a suitable integral length again at suitable integral length such that the hypotenuse is of required length as per the pythagoras theorem. then measuring the hypotenuse with compass and plotting it on number line
 
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While square roots can be constructed, a line with length corresponding to pi cannot be constructed, due to pi being transcendental. You can, however, construct a circle of unit diameter whose circumference will be pi.
If you just want the decimal value of pi, many numerical algorithms exist that converge to multiples of pi, including the Newton-Raphson method, or Taylor series of trigonometric functions.
 
Last edited:
Ask your self, what is a number line and how do you plot 1 on it?
For example:
Code:
0        Pi
__________
There I've plotted Pi on that number line.
 
Zurtex said:
Ask your self, what is a number line and how do you plot 1 on it?
For example:
Code:
0        Pi
__________
There I've plotted Pi on that number line.

Perhaps you should ask yourself those questions. It was clear from the original post that he meant "constructing" a line segment of length pi, using compass and straightedge, given a line segment of length 1.
 
HallsofIvy said:
Perhaps you should ask yourself those questions. It was clear from the original post that he meant "constructing" a line segment of length pi, using compass and straightedge, given a line segment of length 1.
Oh I see, sorry, I read the post only very quickly and that kind of request didn't seem to belong in a Numer Theory forum...
 
please explain Newton Raphson method.

this the not the place forsuch request- Zurtex.
which is the riht place then. i thought number theor page would help me more because this subject would have moretheorems and formulae to deal with such problems

i think the plotting of e is also done with Taylor series. please briefly explain the procedure for both of these cases
 
vaishakh said:
please explain Newton Raphson method.
...
i think the plotting of e is also done with Taylor series. please briefly explain the procedure for both of these cases
A basic calculus course would cover both algorithms. The Newton-Raphson method is a simple way of finding roots of equations, while Taylor series are infinite series expansions of analytic functions. They both deal with derivatives and can be found in the first few chapters of any (beginning) calculus text.
As an example, we know that sin(pi) = 0, so the root of the equation sin(x)=0 in the neighborhood around pi should yield pi if Newton-Raphson is applied. Use http://planetmath.org/encyclopedia/NewtonsMethod.html . Note the domain of convergence; you'll have to choose a fractional multiple of pi, then multiply your calculation by the denominator.
More number theoretic approaches to calculating pi can be found on the page linked to in your other post.
 
Last edited by a moderator:
Pi can not be constructed by ruler and compass.But,Pi may be constructed with the help of some other things other than compass and non-marked ruler.
 

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