Deutsch English Français Italiano |
<52CdnZUf4aEIldz7nZ2dnZfqnPSdnZ2d@giganews.com> View for Bookmarking (what is this?) Look up another Usenet article |
Path: ...!Xl.tags.giganews.com!local-1.nntp.ord.giganews.com!news.giganews.com.POSTED!not-for-mail NNTP-Posting-Date: Sun, 12 May 2024 18:21:09 +0000 Subject: =?UTF-8?Q?Re:_universal_quantification=2c_because_g=e2=a4=a8=28g?= =?UTF-8?B?4oG7wrkoeCkpID0gZyh5KSBbMS8yXSBSZTogaG93?= Newsgroups: sci.math References: <qHqKnNhkFFpow5Tl3Eiz12-8JEI@jntp> <ceecnRqey7PiQ6b7nZ2dnZfqnPSdnZ2d@giganews.com> <e533e6c1-e2a5-48bf-a921-0133d13323c3@att.net> <4nidnfx6cPrst6D7nZ2dnZfqn_adnZ2d@giganews.com> <a67efe1b-dfeb-4aaa-bb4a-8bea6b64f2ee@att.net> <Jm-dnTTO1LWh4aD7nZ2dnZfqn_adnZ2d@giganews.com> <fa182313-6860-4e05-a103-2737336b55ce@att.net> <aAidnSzcCMwa4qP7nZ2dnZfqnPadnZ2d@giganews.com> <58fcd3ad-ba5f-43e5-83e5-364d36a05bb6@att.net> <96icnX-9Eoi7JKP7nZ2dnZfqn_idnZ2d@giganews.com> <9b151f0f-bd31-4652-a216-d769a6d36b39@att.net> <b3ednaXHZ4pH6aL7nZ2dnZfqnPudnZ2d@giganews.com> <5ea7e2c8-3fa4-4a56-843c-2cec222db3ec@att.net> <ToWdnXuzm82dDqL7nZ2dnZfqnPadnZ2d@giganews.com> <fd6c1cae-9d52-4dde-bd4a-3d00f0463560@att.net> <TQ2dnVA9fI8oQKL7nZ2dnZfqn_SdnZ2d@giganews.com> <58KdnWH_rOEle6L7nZ2dnZfqn_WdnZ2d@giganews.com> <XrKdnc5-cvSUZqL7nZ2dnZfqn_qdnZ2d@giganews.com> <a4700775-be6c-46db-ad41-361eee6a3b67@att.net> <SuOcne8WDcEmhd37nZ2dnZfqnPSdnZ2d@giganews.com> <4b86a394-467c-45c4-9370-4efae42ebcd7@att.net> From: Ross Finlayson <ross.a.finlayson@gmail.com> Date: Sun, 12 May 2024 11:21:23 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <4b86a394-467c-45c4-9370-4efae42ebcd7@att.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Message-ID: <52CdnZUf4aEIldz7nZ2dnZfqnPSdnZ2d@giganews.com> Lines: 229 X-Usenet-Provider: http://www.giganews.com X-Trace: sv3-VB50WsIM6e1fTl3T9OG87h/CQe/6hTY7MC9clV+YWQMOB136m0N7QS3PBI1lqYVn4VtKL8Sq2jMmYDF!H5IZk/H1ljuiPRqPOHKylJAFHDOxKeQz8vF5XXUj89fU9bgK/8YY3OHzGZ63BEhrIBLcLyzwJk// X-Complaints-To: abuse@giganews.com X-DMCA-Notifications: http://www.giganews.com/info/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Bytes: 10519 On 05/12/2024 10:46 AM, Jim Burns wrote: > On 5/11/2024 9:17 PM, Ross Finlayson wrote: >> On 05/11/2024 04:47 PM, Jim Burns wrote: >>> On 5/11/2024 7:11 PM, Ross Finlayson wrote: > >>>> The case is that induction goes through, >>>> an inviolable law you call it: >>>> does it go all the way through? >>>> Does it complete? >>> >>> It is complete. >>> There is no completing.activity, >>> so I wouldn't say it completes. >>> >>> Compare to right triangles: >>> Are all the squares of two shorter sides >>> summed to the square of the longest side? >>> >>> That's a tricky question to answer because >>> there is no summing done. >>> That relationship between the sides >>> is simply something true about right triangles. >>> >>> And it is complete == it is true for each. >>> >>> We don't typically ask the tricky question >>> about right triangles. >>> We ask the tricky question about cisfinite induction >>> because we imagine it as a process, >>> which we don't for right triangles. >>> >>> Cisfinite induction is NOT a process. >>> Cisfinite induction is an argument, >>> completely correct or completely incorrect. > >> What I recall of the context of the Pythagorean theorem, > > Let's refresh our memories. > > ͨₐ🭢🭕🭞🭜🭘ᵇ = ͨₐ🭢🭕ͩ + ͩₐ🭞🭜🭘ᵇ > > The right triangle 🞃cab is split into > two right triangles ◥cda ◤adb > by segment a͞d perpendicular to b͞c > > 🞃cab ◥cda ◤adb are _similar_ > [1] > Corresponding sides have equal ratios. > > ∠acb = ∠dca > ∟cab = ∟cda > 🞃cab ≚ ◥cda > c͡b/c͡a = c͡a/c͡d > > ∠cba = ∠abd > ∟cab = ∟adb > 🞃cab ≚ ◤adb > c͡b/b͡a = b͡a/d͡b > > c͡b⋅c͡d = c͡a² > c͡b⋅d͡b = b͡a² > c͡b⋅(c͡d+d͡b) = c͡b² = c͡a² + b͡a² > QED > > [1] needs its own proof, > but that can be done, too. > >> What I recall of the context of the Pythagorean theorem, >> was that after algebra already was trigonometry, and >> the definitions of the trigonometric functions, for >> sine and cosine and tangent, about the opposite and >> adjacent and hypotenuse, then as of a right triangle >> with its hypotenuse the radius of a unit circle, that >> the right angle is as with regards to the abscissa >> and ordinates or where the lines drop or slide to >> the x or y axis of the usual X-Y coordinate setting >> of a circle centered at the origin, it was of the >> secondary school's first three years of geometry, >> algebra, and trigonometry, or along those lines. >> >> So, we computed a bunch of ready things about >> those often with the Pythagorean theorem, >> which is as an addition-formula, mostly about >> 30-60-90 triangles, and, isosceles triangles, >> or 45-45-90, then those got used throughout >> precalculus and a couple years of calculus >> or high school. > > I agree that the Pythagorean theorem > gets used in a lot of different ways. > > How we know that the Pythagorean theorem > is a fact about each right triangle > has important similarities to > how we know that we cisfinitely.induced claims > are facts about each natural number. > >> So anyways one time I see a diagram about >> Pythagorean triples, those being tuples of >> three integers that have a^2 + b^2 = c^2, >> and what they'd done was right triangle, >> then draw a square as of the square alongside >> it, and counting the boxes of the squares of >> a b c it's that the boxes of the squares of a >> and b equals the boxes of the square of c. > > Actually, > that works in the opposite direction. > We know that 3:4:5 is a right triangle > because of the Pythagorean theorem. > >> If that's not a proof of the Pythagorean theorem >> and least it's graphically intuitive for some values, >> where of course there are hundreds of known >> proofs of the Pythagorean theorem, since the >> time of Pythagoras as some even have as from >> greater antiquity, then it reminds of things >> like Rodriguez formula, Vieta's formulas, >> Nicomachus' theorem and formulas, >> Pascal triangle and bonomial theorem, >> all what are sorts of addition formulas, >> like an addition formula of the product >> of exponents as the sum of the powers. >> >> So, that Pythagorean triples exist, and it results >> that the rightness of a triangle with sides length >> the Pythagorean triple can be established without >> invoking the Pythagorean theorem, doesn't so >> much make it so the other way around, from >> induction over Pythagorean triples, without >> showing as how all right triangles are somehow >> as some congruence to what is some Pythagorean >> triple, > > We shouldn't want to show that > each right triangle has a Pythagorean triple, > because we know that isn't true. > Famously, Pythagoras executed one of his disciples > for proving that the right isosceles triangle 1:1:√̅2 > has no Pythagorean triple. > >> of the equivalence class of all the triples >> and all the congruences to triangles with a >> unit length longest side, establishing infinite >> expressions, and closures, of completion, >> to make a case for the Pythagorean theorem >> as via induction from an explication after >> the enumeration of Pythagorean triples, >> which via inspection have a^2+b^2 = c^2, >> as for that it results congruences that >> "go to" any given dimensions of a right >> triangle. >> >> About the cisfinite and transfinite induction, >> and I know it's not the languages fault that ========== REMAINDER OF ARTICLE TRUNCATED ==========