Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ ¹ ² ³ °
 

You are not logged in. #1 20120421 17:20:35
Area of Polygon by DrawingA new app tentatively titled: Area of Polygon by Drawing "The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  Leon M. Lederman #2 20120421 18:29:53
Re: Area of Polygon by Drawinghi MathsIsFun, You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei #3 20120421 19:12:49
Re: Area of Polygon by DrawingHi MIF; In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #4 20120421 20:16:19
Re: Area of Polygon by DrawingNew point: half way between first 2 points.
On your feet, or hands? "The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  Leon M. Lederman #5 20120421 21:57:03
Re: Area of Polygon by DrawingHi MIF;
Hmmmm, those are fine. What would be nice is a few more digits for the area and points. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #6 20120422 00:39:05
Re: Area of Polygon by DrawingI like it,but it cannot be moved left,right,up and down. Last edited by anonimnystefy (20120422 00:39:17) The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #7 20120422 08:17:21
Re: Area of Polygon by Drawing
Click on left of drawing surface to "recenter" half way to right. "The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  Leon M. Lederman #8 20120422 08:24:34
Re: Area of Polygon by DrawingI'll try that tomorrow. The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #9 20120423 11:18:48
Re: Area of Polygon by DrawingAdded an "edit" button so you can manually change all coords. (Use refresh for latest version) "The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  Leon M. Lederman #10 20120423 11:29:43
Re: Area of Polygon by DrawingHi MIF; In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #11 20120423 12:22:31
Re: Area of Polygon by DrawingI am not sure what that is,but I think it is a: The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #12 20120423 14:11:44
Re: Area of Polygon by DrawingYes, anonimnystefy, A+ "The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  Leon M. Lederman #13 20120423 15:04:22
Re: Area of Polygon by DrawingA winner is me ." The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #14 20120514 17:58:45
Re: Area of Polygon by DrawingNew version 0.75 "The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  Leon M. Lederman #15 20120514 19:08:37
Re: Area of Polygon by DrawingHi MIF; In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #16 20120514 20:56:44
Re: Area of Polygon by DrawingHi bobbym The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #17 20120514 20:59:00
Re: Area of Polygon by DrawingSorry, I can not even remember what day it is and you want me to remember what these formulas are called? In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #18 20120514 21:04:34
Re: Area of Polygon by DrawingDid you try searching "shoelace formula" to see if that is the one? The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #19 20120514 21:12:35
Re: Area of Polygon by DrawingHeck no! That is most convoluted idea I have ever seen. I just plug them into a big matrix and let M get the determinant. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #20 20120514 21:14:27
Re: Area of Polygon by DrawingPlug what into a big matrix? The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #21 20120514 21:15:28
Re: Area of Polygon by DrawingThe coordinates. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #22 20120514 21:16:16
Re: Area of Polygon by DrawingWhat kind of matrix? What are the dimensions? The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment #23 20120514 21:17:59
Re: Area of Polygon by Drawing
Same, really. Sum up (pt0.x * pt1.y  pt0.y * pt1.x) for successive pairs of points (including last to first). Need to divide by 2 at end. "The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  Leon M. Lederman #24 20120514 21:20:56
Re: Area of Polygon by DrawingSorry, I seemed to have dropped the determinant way in favor of some algorithm. This is the one I have in my notes right now. I was wondering what MIF is using In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #25 20120514 21:21:34
Re: Area of Polygon by DrawingDoes the same method work for complex polys? The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment 