![]() |
If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
|
#1
|
|||
|
|||
![]()
On Thu, 2 Nov 2006 10:38:41 -0600, Kevin Vang wrote:
In article , says... According to your theory, that dart can easily and readily strike any point on the disk or any point outside of the circumference created by the selection of the first and second points, up to and including "un-measurably" close to the inside or the outside of the circumference, but can never actually strike a point on the circumference. IOW, the third point (Dart C) can only create a second radius that must be less than or greater than the first radius. With not being able to select a second point on the circumference, arcs, in such a world, don't exist. If arcs don't exist, geometry, trig, etc. begins to break down. In the failure cascade of interrelated bits , it takes all math down with it. It's not that the arc doesn't exist, and we cannot choose points on that arc. The point is that the probability of hitting that arc with a dart is 0. Intuitive explanation: Suppose your dartboard has radius 1. Throw a dart at the dartboard, and let r1 = radius from the center of the dartboard to the dart. Now throw a second dart, and let r be the radius. Then the probability that r = r1 is number of values of r for which r = r1 1 ------------------------------------------- = ------------ = 0. number of possible values for r infinity More technical (and more correct) explanation: If we assume that every point on the dartboard is equally likely to be hit, then the probability that r = r1 is: measure of the set for which r = r1 0 -------------------------------------- = ------------ = 0 measure of the dartboard pi * 1^2 because the dartboard is a 2-dimensional surface, the appropriate measure is area. The measure of the entire dartboard is the area of a circle with radius 1, so the area is pi*1^2 = 1. The set of points for which r = r1 is the circle with radius r1. Since the circle is just a curve with width 0 on the plane, it has area 0. Slightly more technical (and more correct): Not every point on the dartboard is equally likely to be hit. Apparently. The word on the street is that at least some are completely unhittable, what with the probability of doing so being zero or infinitely small or pi-r-square or, well, something all dangerously full of symbols and greek letters and ****... If p(r,theta) is the probablility density function giving the probability that the dart hits point (r,theta) in polar coordinates, then the probability that r = r1 is: / r1 | p(r,theta) dA / r1 0 ------------------------- = --- = 0 / 1 1 | p(r,theta) dA / 0 because we are integrating with respect to area, and the top integral is done over a region with area 0, so the value of the integral is 0. SEE! SEE! I WARNED YA, BUT NOO-O-O-O-O... IAC, three answers, each "and more correct" than the previous one. Interesting. Is this progression going to lead to something infinitely correct (or something to at least stick a fork in and call "done"), or is the probability of hitting that target zero, too? HTH, Kevin And I'm pretty certain that mathematics doesn't all disappear if somebody doesn't understand one bit of it. Hey, go easy on me, I'm learning...for example, I've already learned that when 2 math whiz-types and a rat-gutter answer a question, the odds that they will come up with the correct answer is like one in a gazillion or bazillion or some other REALLY big ol' number... And right back at ya, Pythagoras R |
#2
|
|||
|
|||
![]() wrote in message ... On Thu, 2 Nov 2006 10:38:41 -0600, Kevin Vang wrote: In article , says... According to your theory, that dart can easily and readily strike any point on the disk or any point outside of the circumference created by the selection of the first and second points, up to and including "un-measurably" close to the inside or the outside of the circumference, but can never actually strike a point on the circumference. IOW, the third point (Dart C) can only create a second radius that must be less than or greater than the first radius. With not being able to select a second point on the circumference, arcs, in such a world, don't exist. If arcs don't exist, geometry, trig, etc. begins to break down. In the failure cascade of interrelated bits , it takes all math down with it. It's not that the arc doesn't exist, and we cannot choose points on that arc. The point is that the probability of hitting that arc with a dart is 0. Intuitive explanation: Suppose your dartboard has radius 1. Throw a dart at the dartboard, and let r1 = radius from the center of the dartboard to the dart. Now throw a second dart, and let r be the radius. Then the probability that r = r1 is number of values of r for which r = r1 1 ------------------------------------------- = ------------ = 0. number of possible values for r infinity More technical (and more correct) explanation: If we assume that every point on the dartboard is equally likely to be hit, then the probability that r = r1 is: measure of the set for which r = r1 0 -------------------------------------- = ------------ = 0 measure of the dartboard pi * 1^2 because the dartboard is a 2-dimensional surface, the appropriate measure is area. The measure of the entire dartboard is the area of a circle with radius 1, so the area is pi*1^2 = 1. The set of points for which r = r1 is the circle with radius r1. Since the circle is just a curve with width 0 on the plane, it has area 0. Slightly more technical (and more correct): Not every point on the dartboard is equally likely to be hit. Apparently. The word on the street is that at least some are completely unhittable, what with the probability of doing so being zero or infinitely small or pi-r-square or, well, something all dangerously full of symbols and greek letters and ****... If p(r,theta) is the probablility density function giving the probability that the dart hits point (r,theta) in polar coordinates, then the probability that r = r1 is: / r1 | p(r,theta) dA / r1 0 ------------------------- = --- = 0 / 1 1 | p(r,theta) dA / 0 because we are integrating with respect to area, and the top integral is done over a region with area 0, so the value of the integral is 0. SEE! SEE! I WARNED YA, BUT NOO-O-O-O-O... IAC, three answers, each "and more correct" than the previous one. Interesting. Is this progression going to lead to something infinitely correct (or something to at least stick a fork in and call "done"), or is the probability of hitting that target zero, too? HTH, Kevin And I'm pretty certain that mathematics doesn't all disappear if somebody doesn't understand one bit of it. Hey, go easy on me, I'm learning...for example, I've already learned that when 2 math whiz-types and a rat-gutter answer a question, the odds that they will come up with the correct answer is like one in a gazillion or bazillion or some other REALLY big ol' number... And right back at ya, Pythagoras Hee, hee, hee. Wolfgang is it just me or has anyone else noticed that the probability of surrenders in general (and dicklet's in particular) being gracious tends to decrease over time? |
Thread Tools | |
Display Modes | |
|
|