neilparker62's latest activity
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neilparker62 reacted to DaveC426913's post in the thread There Be Monsters by Dave Collins with
Like.
I finished - and printed - my collection of short stories! There Be Monsters A collection of fantastical maritime-themed short stories... -
neilparker62 replied to the thread Prove that ## 4\tan^{-1}\left[\dfrac{1}{5}\right]- \tan^{-1}\left[\dfrac{1}{239}\right]= \dfrac{π}{4}##."All in one" derivation of compound angle formulae - based on the video construction.
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neilparker62 replied to the thread Prove that ## 4\tan^{-1}\left[\dfrac{1}{5}\right]- \tan^{-1}\left[\dfrac{1}{239}\right]= \dfrac{π}{4}##.Neat geometric derivation of ##\tan(A+B)=\frac{\tan A + \tan B}{1-\tan A \tan B}## if we divide all terms in ##\frac{ay+bx}{by-ax}## by...
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neilparker62 reacted to Steve4Physics's post in the thread Prove that ## 4\tan^{-1}\left[\dfrac{1}{5}\right]- \tan^{-1}\left[\dfrac{1}{239}\right]= \dfrac{π}{4}## with
Informative.
For an essentially geometric proof (no standard trig' identities used) see this 3 minute (appox.) video. -
neilparker62 replied to the thread Prove that ## 4\tan^{-1}\left[\dfrac{1}{5}\right]- \tan^{-1}\left[\dfrac{1}{239}\right]= \dfrac{π}{4}##.$$\tan x=\frac{1}{5} \implies \tan2x=\frac{5}{12} \implies \tan4x=\frac{120}{119}$$ $$\tan \left( \tan^{-1} \left( \frac{1}{239}...
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neilparker62 commented on neilparker62's profile post.It will highlight your solution as well as illustrate a treasure trove of underlying geometry 'dug up' by AI. I will include an...
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neilparker62 commented on neilparker62's profile post.Ok - so what I was thinking of doing is writing a short article on one of your many interesting posts and subsequent threads...
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They've said that about programmers and the people who worked as computers. We see an efficiency, adopt the new tech. Some folks lose...
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neilparker62 commented on neilparker62's profile post.Hi again. I don't think there is anything like an "official" pf letterhead since it's just a website. But you can check with @Greg...
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neilparker62 left a message on chwala's profile.Hi. Did you get your reference from someone on PF ? I can write something like I see you regularly posting interesting Maths/geometry...
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neilparker62 replied to the thread Doppler effect: why do I find this exercise so difficult?.Thanks for the link.
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neilparker62 reacted to Steve4Physics's post in the thread Doppler effect: why do I find this exercise so difficult? with Like.
That’s a nice approach. A copy of the article can be found here: https://arxiv.org/pdf/2504.18159 Also, the equation...
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neilparker62 reacted to physicsstudent21's post in the thread Doppler effect: why do I find this exercise so difficult? with Like.
After reading the following article, your understanding to the Doppler effect will be much more clear. You may find this article by...
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Thanks a lot everyone
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Ah yeah of course. It's a diverse field of knowledge and the OP's interests were/are pretty specific. It was just your list of trophies...
