Gavran's latest activity

I voted no for colony but I do not think it would out of the question to have a permanent scientific base there.

This can also be shown in the following way. ## \begin{align} &\arctan\frac\alpha c+\arctan\alpha=\arctan c\nonumber\\...

It can be shown that the yellow figure of the last graphic in post #8 can be completely contained in the blue figure. Take off an...

I noticed the following question generated quite a lot of interest on the Internet. Which is larger ##e^{\pi}## or ##\pi^e##? Most (if...

That's incorrect. The ability of a material to shield and channel magnetic fields is measured by its relative-permeability ##\mu_R\,##...

Sorry for late reply Thank you very much for the help and explanation berkeman, kuruman, Steve4Physics, Gavran

The equation ## C=A+B ## is actually Euler's formula $$ \arctan\frac12+\arctan\frac13=\frac\pi4 $$, and there are three more formulas of...

Here is another way but it’s just a variation of @coquelicot above in post #7 but the lengths are not obvious so they must be...

a different line for ##\tan 4S## ##\tan (4S)= \tan (2S +2S) = \dfrac{\tan 2S + \tan 2S}{1 - \tan^2 (2S)}## ##\tan (2S) =...

There are four formulas of this kind. Euler's formula $$ \arctan\frac12+\arctan\frac13=\frac\pi4 $$ Hermann's formula $$...

Based on the previous posts, it can also be shown that A+B+C=D for the angles A, B, C, and D in the next picture. Or A+B+C+D=E for...

Here are some more solutions; In each case, the triangle constructed in green is similar to the triangle highlighted in brown which...

Just another approach:

I think you are right, and the correct answer is d. A copper shield can be better than a steel shield against a high-frequency magnetic...