Maple 2019 Questions and Posts

These are Posts and Questions associated with the product, Maple 2019

How to make the matrix construction by points animated?
I sketched this code - it doesn't work(((

a := Matrix([stoimostyM, izmeniya]);
plots[animate](plot, [a[n, m]], n = 1 .. 2970, m = 1 .. 2, numpoints = 50, frames = 100);
Error, bad index into Matrix

4/(9*n + 7*sqrt(n)) <= 4/(9*n + 7*sqrt(n))

Hi I am trying to plot in maple but the plot I get is not the one I expect I have attached the maple file and the expected image below. Any help would be appreciated. 



This is perhaps a stupid question, when I use the ScientificConstant package and call a constant e.g. R this works smoothly. But when I assign the value to a variable to use it in a calculation Maple complains about the units. However, if I assign the constant manually (without using GetConstant) Maple has no issues in solving. Is there a trick to use such a constant in a calculation? I have attached a worksheet to illustrate my question better. Thank you in advance for helping me


I want to declare 'd' as a constant.

Please tell me how to declare 'd' as a constant.

I need the Infinitesimals(Lie group analysis) of the system of PDE. I have attached below the system of PDE in MAPLE given

Thank you


I am trying to solve the following system of odes where the unknowns are xhat, yhat, uhat and vhat. They depend on the variables (x, y, u, v, a_1, a_2, a_3, a_4, f(x)) where f(x) is an arbitrary function and I want to solve it with respect to a_1. The RHS has f(x) and its derivative with respect to x. The dsolve function fails to solve the ode when I add f(x) at the list of variables. 

vars := x, y, u, v, a_1, a_2, a_3, a_4, f(x);
sys_ode := diff(xhat(vars), a_1) = a_3*x + a_1, diff(yhat(vars), a_1) = a_2 - a_4*y + f(x), diff(uhat(vars), a_1) = a_3*u + 2*a_4*u, diff(vhat(vars), a_1) = a_4*v + diff(f(x), x)*u;

initvars := x, y, u, v, 0, a_2, a_3, a_4, f(x);
ics := xhat(initvars) = x, yhat(initvars) = y, uhat(initvars) = u, vhat(initvars) = v;
solution_a1 = dsolve([sys_ode, ics], [xhat, yhat, uhat, vhat]);

Can anyone help regarding this issue ?


how to find the solutions of a system of recursive equations? And the plot too.

I tried but...

B := rsolve({a(0) = 0, a(i) = (1 + 10^(-5)*(0.01*(i - 1) - 0.007)/0.0001)*a(i - 1) + 0.1*10^(-5)*c(i - 1), c(0) = 0, c(i) = 0.01*10^(-5)*(i - 1)/0.0001*a(i - 1) + (1 - 10^(-5))*0.1*c(i - 1)}, {a(i), c(i)}, 'genfunc'(t));
B := rsolve({a(i) = (0.9983000000 + 0.001000000000 i) a(i - 1)

   + 0.000001000000000 c(i - 1), 

  c(i) = 0.001000000000 (i - 1) a(i - 1) + 0.09999900000 c(i - 1)

  }, {a(i), c(i)}, genfunc(t))


I am trying to start writing small procedures in Maple. In the attached document I do not get an answer and I do not understand why. For clarity I have also added a working construct from another program so anyone willing to help me out can better understand what I am after.

Thanks in advance for assistance.

First of all I would like to wish everyone a happy, prosperous and especially healthy 2022!

I do not understand why my second formula in the attached sheet gives the wrong answers. I have added the correct answers in the vector "Correct". I still find it a bit cumbersome to work elementwise in Maple but that is most likely because still being relatively new to the program. Any help is more than appreciated 

Hi everyone. 

I need a program in maple to simulate the orbit of a satellite slowed down by the earth's atmosphere.

I chose the simple case, in which the orbits of the two are elliptical and I use The animation to do this. In this case I did not consider that the satellite interacts with the atmosphere.

Now,  I need equations to write part of the program in which I think the satellite is slowed down by the earth's atmosphere. I don't have any ideea to resolve this problem.

Soo.. I really need your' help as soon as posible.

Thank you a lot! 

# Below you find a small example about the function diffdiameter(conc,number), which has the unit length as long as the second argument number is not zero. Using the convert function it is possible to remove the units entirely, but this does not help, if I want to plot the functions. Is there a possibilty to plot diffdiameter(conc,number-not-zero) and diffdiameter(conc,0) in one diagramm? with(Units[Simple]); with(plots); diffdiameter := (conc, number) -> -number*diameter*exp(-conc/Unit(mol/kg)); diffdiameter := proc (conc, number) options operator, arrow; Units:-Simple:-`-`(Units:-Simple:-`*`(Units:-Simple:-`*`(numb\ er, diameter), Units:-Simple:-exp(Units:-Simple:-`-`(Units:-Si\ mple:-`*`(conc, Units:-Simple:-`/`(Unit(Units:-Simple:-`*`(mol\ , Units:-Simple:-`/`(kg))))))))) end proc diameter := 2*Unit(m); diameter := 2 Unit(m) evalf(diffdiameter(Unit(mol/kg), 6)); evalf(diffdiameter(Unit(mol/kg), 0)); -4.414553294 Unit(m) 0. convert(evalf(diffdiameter(Unit(mol/kg), 6)), unit_free); convert(evalf(diffdiameter(Unit(mol/kg), 0)), unit_free); -4.414553294 0. plot([convert(evalf(diffdiameter(conc, 0.001)), unit_free), convert(evalf(diffdiameter(conc, 6)), unit_free)], conc = 0 .. 4*Unit(mol/kg), title = "derivative Diameter with conc", labels = ["concentration / mol/kg", "deriv diameter / m"], color = ["blue", "red"], legend = ["bare diameter", "PLUS diameter"], labeldirections = ["horizontal", "vertical"], titlefont = [Helvetica, bold, 16], axesfont = [Helvetica, 14], labelfont = [Helvetica, 14], axes = boxed); plot([convert(evalf(diffdiameter(conc, 0)), unit_free), convert(evalf(diffdiameter(conc, 6)), unit_free)], conc = 0 .. 4*Unit(mol/kg)); Error, (in plot) invalid subscript selector

Under maple 2019 (linux ubuntu) I cannot make 3d plots !



does not produce any output and also the worksheet does not react any more. The only way to get out is to quit.

Btw: 2d plots work fine ...

What is wrong ? Thank you. Bs regards, Malte.


How to put a function in the ODE. I have attached below work here.

Thank you


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