Recent content by Tommaso_Russo

It's simply impossible. Decompose your numbers in prime factors: 14 is 2x7, 34 is 2x17, 84 is 2x2x3x7, 60 is 2x2x3x5. When you couple two gearwheels with N1 and N2 teeth, their rotational speed ratio is the rational (Oh really? :smile:) number N1/N2; for a gear train, will be...

You are 28, not 18, so... I meant: you are not a young student looking for solutions to a homework; so. I tought you were a technician or a researcher needing that integral for some computations. In such cases, the fast way is just Wolfram Alpha. Reading also what you have written in the...

You are 28, not 18, so... quick and dirty: http://www.wolframalpha.com/input/?i=integrate+1%2F%289%2B7*%28sinx%29^2%29+from+x%3D0+to+x%3Dpi

You've got different answers because your question isn't clear. What do you mean by "point of contact"? Three possible interpretations and related answers: 1) a virtual point that moves along the surface so as to coincide always with the surface's point that touches the sphere. Its speed is...

HI, while writing a post, I opened the attachment window and uploaded 5 files. When I could go back to the editing window, I found that my token was expired, and could not complete my post. Unfortunately, I closed all windows. So, now there are 5 unused files in the forum's memory, but...

I had the same problem an could find none, so I did it myself. Of course there is. They are just Lorentz transformations of the EM tensor passing from the reference system in which the charge is at rest to a reference system in which it's moving with speed -v: in SI units, E'x = Ex...

mmm... x=a^2-b^2=(a+b)(a-b) but a-b = 1 so x = a+b = 444,444,444,444,444,444,443

Sorry, but near 44° there is no geometrically valid solution. I suppose you have found 43.767° as arctan of one of the solutions of your quartic in t. But that solution for t is also tan(180°+43.767°), and is that value that solves original equations, but with a negative value for the inner...

Ah, OK. I understand well your surprise, because I too wondered why phi2+180° and phi3+180° are not solutions with a reverse sign for a side of inner rectangle: if real, Phi2 and phi3 are true solutions, I give an example below. phi2+180° and phi3+180° are solutions of same equations, if you...

It's simple: the fourth solution for phi is always out of the allowed range 0°-90°, and corresponds to a negative side for the inner rectangle. If you give to gnuplot the command sequence given above, but replacing [FONT="Courier New"]set xrange [0:90] with [FONT="Courier New"]set xrange...

No problem. You can use Pythagorean Theorem without knowing any of its many proofs. What you need is exactly subroutine [FONT="Courier New"]find_angles_numerically; and other subroutines it calls. In short, all fortran subprograms written for case 3c). [FONT="Courier...

I guess that one thing you have not grasped is that, given A,B,Y, the solution for phi is not necessarily unique. You can obtain one to three values for phi that allow you constructing a rectangle XY thath turns out to be perfectly inscribed into AB. Of course, to each value found for phi...

Hi, I've posted general solutions for all these kinds of problems in a new thread: https://www.physicsforums.com/showthread.php?t=508715 sorry for the delay, it was not easy. -- TRu-TS Buon vento e cieli sereni

Ciao to everybody, I've encountered frequently, in forums and news groups, questions about a rectangle inscribed in another rectangle, but nowhere a general discussion on ways to solve related problems (i.e., given three of the five quantities involved - 2 sides of outer rectangle, 2 sides...