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Re: Refreshing grade school math.

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On Monday, January 13, 2020 at 11:58:36 AM UTC-6, Jonas Thörnvall wrote:

> But i think you missed the question completly?
> How to do it withoug use of angles "cosin sinus".
> 
> Here it is without but, but i have tried to think about howto actually get x "nodes/vertices" evenly spaced without use "sin cosin" using just algebra or geometry. And i "think" it will use an equation system with two equation to solve the cordinates around the arcs.
> 
> So can you do it, i sure i could some years ago, but i am not that sure any longer.


In elementary/primary school you should have learned the equation for a circle:

x^2 + y^2 = r^2

Alternate form to solve for y:

y = +/- sqrt(r^2 - x^2)

That's enough for you to plot your points.

Assuming a circle of radius 5 and centered at the origin (0,0)

iterate x from -r to +r and solve for y:

y = +/- sqrt((5)^2 - (-5)^2)
  = +/- sqrt(25 - 25)
  = +/- sqrt(0)
  = +/- 0
  = 0
y = +/- sqrt((5)^2 - (-4)^2)
  = +/- sqrt(25 - 16)
  = +/- sqrt(9)
  = +/- 3
y = +/- sqrt((5)^2 - (-3)^2)
  = +/- sqrt(25 - 9) 
  = +/- sqrt(16) 
  = +/- 4
...

now convert that to JavaScript

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Thread

Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-08 23:54 -0800
  Re: Refreshing grade school math. "R.Wieser" <address@not.available> - 2020-01-09 09:19 +0100
    Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-09 00:34 -0800
      Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-09 00:43 -0800
        Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-09 00:44 -0800
    Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-11 05:09 -0800
      Re: Refreshing grade school math. Julio Di Egidio <julio@diegidio.name> - 2020-01-11 22:13 -0800
        Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-13 09:58 -0800
          Re: Refreshing grade school math. Julio Di Egidio <julio@diegidio.name> - 2020-01-13 10:16 -0800
            Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-13 11:16 -0800
          Re: Refreshing grade school math. "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2020-01-13 12:22 -0800
            Re: Refreshing grade school math. Julio Di Egidio <julio@diegidio.name> - 2020-01-13 12:53 -0800
              Re: Refreshing grade school math. "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2020-01-13 15:31 -0800
              Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-13 16:03 -0800
            Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-13 13:00 -0800
              Re: Refreshing grade school math. "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2020-01-13 15:35 -0800
                Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-13 15:43 -0800
            Re: Refreshing grade school math. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2020-01-14 01:01 +0100
              Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-13 16:07 -0800
        Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-13 10:01 -0800
        Re: Refreshing grade school math. Jonas Thörnvall <jonas.thornvall@gmail.com> - 2020-01-13 10:04 -0800

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