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Christos Papahristodoulou
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*MODERATOR NOTE: coronavirus resources & updates:* https://wolfr.am/coronavirus ---------- Christos Papahristodoulou May 29, 2020 The three Nordic countries together, Denmark, Norway and Finland had in May 28, almost 200 deaths per...
*MODERATOR NOTE: coronavirus resources & updates:* https://wolfr.am/coronavirus ---------- In this document I apply the standard SIRD model , using Italian COVID19 data. Up to date, May 23, there are 89 daily observations, starting from...
Help please! I have a manipulated graph programmed in Version 11, which worked perfectly, but when I run it with version 12, it works, but a "red" area appears with the error "A tick position in the value of the Ticks option should be a number. ". I...
I have parametrized a complex economic growth model and reduced it to a system of 5 linear & non-linear equations, including one parameter with bounds. All solvers (NSolve, FindRoot, FindInstance etc) fail to solve it within 5 minutes with various...
The following function is positive, easy to see it, but Mathematica fails! Why? I have tried with Reduce, and Find Instance or the following. If one sets some parameters, such as T = 60 and S = 20 (in fact T > S) the =0?: Assuming[T > S && r...
Hi! I have tried to solve the following non-linear integer max-problem, without setting some lower (positive) bounds on Q1, Q2 & Q3, just being positive. Mathematica fails to find the optimal solotion, unless I increase the lower bounds for Q2 & Q3...
The data is given by: q = Flatten[ Table[{a, b, c, d}, {a, 0, 1}, {b, 0, 1}, {c, 0, 1}, {d, 0, 1}], 3]. Mathematica gives the following order: {{0, 0, 0, 0}, {0, 0, 0, 1}, {0, 0, 1, 0}, {0, 0, 1, 1}, {0, 1, 0, 0}, {0,...
Hi everyone! I have tried to present my Mathematica documents (.nb or .cdf) to my students in class by connecting my laptop through a projector. Unfortunately I can't see in my computer simultaneously, what is being projected, no matter which...
Hi, The attached file includes my own Demonstration and one found in Wolfram, both created by Mathematica 10 and worked perfectly. When I tried to use it with the new Mathematica 11, it does not work properly (it seems to be the "Epilog" that...
In the following dynamic graph the red team (4-4-2) plays against the blue team (4-3-3). It is better when the red team plays with the slider(t) forward and the blue team backward. Enjoy it! [1]:...