User Portlet
Featured Contributor
| Discussions |
|---|
| &[Wolfram Notebook][1] [1]: https://www.wolframcloud.com/obj/c11e5ca6-7d14-4567-8342-685788cadb08 |
| Hello all, having heateq = D[fT[x, t], t] - a D[fT[x, t], x, x]; fLT = LaplaceTransform[heateq, t, s] (*-fT[x,0]+s LaplaceTransform[fT[x,t],t,s]-a LaplaceTransform[(fT^(2,0))[x,t],t,s]*) is there a more simple and concise way to... |
| In a forgoing post https://community.wolfram.com/groups/-/m/t/2332921 the moment of inertia of a triangle in R2 rotating around a point was calculated. Here a method is given to do this in R3, the triangle rotating around an axis thru x4 ... |
| A couple of hours ago someone asked how to calculate the moment of inertia of a (homogenous) triangle with respect to a point of rotation. I think it could be done like this xx = {{4, 1}, {1, 3}, {2, 7}}; (*start*) rr = {.5, 5}; ... |
| In the notebook attached a procedure is given to calculate the heat of evaporation of a substance from its van der Waals constants. The notebook basically has three parts. In part 1 the single steps are outlined and explained, in part 2 all these... |
| Snooker is a fascinating sport. Just now the UK Championship is taking place. I tried to visualize (in a 1st approximation, things are a bit more complicated in real life) how the cue ball covers an object ball when a certain angle is needed. ... |
| ![enter image description here][1] #Introduction# Many years ago I used to assist my professor in teaching Inorganic Chemistry for beginners. Every now and then when talking about orbitals somebody asked : *"I understand $d(x,y)$ and so, but... |
| By **Albrecht Küster** (hcak@gmx.de) and **Hans Dolhaine** (h.dolhaine@gmx.de) In a foregoing post [https : // community.wolfram.com/groups/-/m/t/1651695?p_p _auth = EmJqMz34][1] Stan Gianzero asked, how the inverse of a 2 x 2 matrix, whose... |
| In a recent thread ( https://community.wolfram.com/groups/-/m/t/1572853 ) the question of linearization of a multinomial was posed. Frank Kampas pointed out that Series has its drawbacks and that something like a Taylor-Series is missing. Frank... |
| Is it this what you want? I tested it with a range from 11 to 111. cc = Range[11,111]; Total[(#[[1]] & /@Select[Transpose[{Times @@ (#^2) & /@ IntegerDigits /@ cc, cc}], #[[1]] |