Steve4Physics's latest activity
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SSteve4Physics reacted to neilparker62'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
Like.
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... -
SSteve4Physics reacted to neilparker62'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
Wow.
"All in one" derivation of compound angle formulae - based on the video construction. -
SSteve4Physics reacted to neilparker62'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 Like.
$$\tan x=\frac{1}{5} \implies \tan2x=\frac{5}{12} \implies \tan4x=\frac{120}{119}$$ $$\tan \left( \tan^{-1} \left( \frac{1}{239}...
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SSteve4Physics replied to the thread Prove that ## 4\tan^{-1}\left[\dfrac{1}{5}\right]- \tan^{-1}\left[\dfrac{1}{239}\right]= \dfrac{π}{4}##.For an essentially geometric proof (no standard trig' identities used) see this 3 minute (appox.) video.
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SSteve4Physics reacted to Greg Bernhardt's post in the thread Praise 2025 PF Member Awards Ceremony with Like.
It's been another incredible year spent on PF! Thanks to all contributing members for making it special! This year we're coming upon 25...
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SJust another approach:
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SSteve4Physics reacted to bob012345's post in the thread High School Three Squares Problem with Like.
Here are some more solutions; In each case, the triangle constructed in green is similar to the triangle highlighted in brown which...
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SSteve4Physics replied to the thread High School Three Squares Problem.The solution below is not mine – I saw it on YouTube, here. This is just my summary. 1. Add 3 squares and consider the triangle...
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SSteve4Physics replied to the thread Rotating difraction grid.With the diffraction grating ('grid') like this: - to which axis of rotation (x, y or z) do you think part a) refers ? - to which axis...
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SSteve4Physics replied to the thread Spring aproximation.SHM requires that the restoring force is proportional to the displacement from the equilibrium position. Find the limit of...
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SSteve4Physics replied to the thread Which material will stop magnetic attraction?.YouTube is your friend (with music)! CLick here. Interesting point. I think the diagram captures the main effect – the re-routing of...
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SSteve4Physics reacted to berkeman's post in the thread Which material will stop magnetic attraction? with
Agree.
Can you post a link to the online question? Obviously any magnetic shielding effect would require a ferrous material. -
SSteve4Physics replied to the thread Which material will stop magnetic attraction?.IMO the answer-key is wrong and the correct answer is d - the steel sheet. Steel* has a high magnetic permeability. A large steel sheet...
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SSteve4Physics reacted to kuruman's post in the thread Finding the acceleration of a block on an inclined plane with friction with Agree.
In addition to @Steve4Physics's comments: 1. Please note that we prefer that you post your work in ##\LaTeX## which makes the equations...
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SSteve4Physics replied to the thread Finding the acceleration of a block on an inclined plane with friction.Welcome to PF! I agree with your results but have some comments. Yes, you have accounted for friction correctly. It is good practice...
