What Is The Root of 5? Irrational

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Discussion Overview

The discussion revolves around the concept of finding square roots of various integers, particularly focusing on the irrational nature of certain roots, and the implications of this on graphical representations in software like AutoCAD and Adobe Illustrator. Participants explore numerical methods for approximation and the visual smoothness of curves in computer graphics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how to find the square roots of several integers and expresses confusion about the smoothness of curves in graphics software if these roots cannot be precisely determined.
  • Another participant asks for clarification on what is meant by "finding the root" and suggests that roots can be approximated to any desired precision.
  • There is a discussion about the approximation of square roots using numerical methods, with one participant mentioning the bisection method as an example.
  • Another participant points out that while the decimal expansion of square roots like \(\sqrt{2}\) is infinite, they still have exact representations, and discusses the role of antialiasing in creating smooth lines on screens.
  • One participant emphasizes that the smooth appearance of curves is an illusion created by the finite resolution of screens and the use of various graphical techniques.

Areas of Agreement / Disagreement

Participants express differing views on the implications of irrational roots for graphical smoothness, with some asserting that approximation methods can yield smooth curves while others question the relationship between approximation and visual representation.

Contextual Notes

There are limitations in the discussion regarding the assumptions about graphical representation and the nature of irrational numbers, as well as the dependence on specific numerical methods for approximation.

Who May Find This Useful

This discussion may be of interest to those exploring numerical methods, computer graphics, and the mathematical properties of irrational numbers.

mymachine
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I wonder how do I find the root of 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 17, and so on?

And why the circle and the curve looks so smooth in the computer graphic software such as AutoCAD, Adobe Illustrator, etc., if the root is can not be found?

It should be looks rough.

Thank you
 
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mymachine said:
I wonder how do I find the root of 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 17, and so on?

And why the circle and the curve looks so smooth in the computer graphic software such as AutoCAD, Adobe Illustrator, etc., if the root is can not be found?

It should be looks rough.

Thank you

What do you mean find the root of those numbers? Do you want an algorithm for finding square roots by hand?

What makes you think the root cannot be found? Are you worried because can't be written as a decimal or fraction to infinite precision? It can be approximated as close as you would like.
 
If it be approximated, then the circle or curve in the computer graphic software should not looks smooth.

How do you approximate the root of 2,3,5,6,7,8,10, and so on?

By the numerical method?
 
mymachine said:
If it be approximated, then the circle or curve in the computer graphic software should not looks smooth.

How do you approximate the root of 2,3,5,6,7,8,10, and so on?

By the numerical method?

Yes, you approximate them. What does that have to do with whether or not the graph "looks smooth"?
 
You have the equation:

x2-c=0 Where c is the number of your choice.

There are lots of numerical methods which can be used on this. The most basic is the bisection method. Just for example let c=6

let x = 1 plug that into the above expression to get -5, now let x = 3, plug that into the equation to get 3, since the first try was negative and the second positive we must have a zero between 1 and 3, cut the interval in half and try x=1.5. What is the sign? It will be either + or -, so you have narrowed the interval where the root lies. Continue this process until you achieve the accuracy you want.
 
While the decimal expansion of the \sqrt 2 is infinite, we have a perfectly valid and exact representation of the number - \sqrt 2.

And lines on the screen look nice because of antialiasing, not for any other reason. Yes, Bresenham's line algorithm or midpoint circle algorithm produce jagged lines, but they are rarely used these days.
 
mymachine said:
And why the circle and the curve looks so smooth in the computer graphic software such as AutoCAD, Adobe Illustrator, etc., if the root is can not be found?

They look so smooth because your eye does not have infinite resolution. You have to remember no matter what your screen is made of discrete pixels so there is no such thing as a continuous curve on the screen, only the illusion of one. Multiple tricks are used to help that illusion out such as smoothing, shading, etc.

In my experience a 32 sided polygon works well for small circles. As you draw bigger and bigger circles you just add more and more sides.
 

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