What Is The Root of 5? Irrational

In summary: This is just a rough guideline, I'm not saying this is how they did or do do it.In summary, the conversation discusses finding the root of numbers and how it relates to the smoothness of circles and curves in computer graphic software. The speaker suggests using numerical methods to approximate the root and explains that the smooth appearance is due to tricks such as antialiasing and discrete pixels. They also mention the use of polygons to create circles.
  • #1
mymachine
42
0
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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  • #2
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.
 
  • #3
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?
 
  • #4
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"?
 
  • #5
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.
 
  • #6
While the decimal expansion of the [itex]\sqrt 2[/itex] is infinite, we have a perfectly valid and exact representation of the number - [itex]\sqrt 2[/itex].

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.
 
  • #7
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.
 

1. What does it mean for a number to be irrational?

For a number to be irrational, it means that it cannot be expressed as a simple fraction of two integers. In other words, it cannot be written as a ratio of two whole numbers.

2. How do you find the root of an irrational number like 5?

To find the root of an irrational number like 5, we use a process called "estimation by successive approximations." This involves repeatedly guessing and refining our estimate until we get closer and closer to the actual value of the root.

3. Is the root of 5 a rational or irrational number?

The root of 5 is an irrational number. This can be proven using the Pythagorean theorem, which states that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides. When applied to a triangle with side lengths of 1, 2, and √5, we can see that √5 cannot be expressed as a ratio of two integers.

4. Can the root of 5 be simplified?

No, the root of 5 cannot be simplified any further. It is already in its simplest form as an irrational number.

5. What is the decimal representation of the root of 5?

The decimal representation of the root of 5 is approximately 2.2360679775, but it is an irrational number, so it has an infinite number of non-repeating digits after the decimal point.

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