Hi everyone, I'm doing a thesis about a solar panel and to extract some parameters from measured data I woudl have to solve 

a set of 3 non-lineair equations. This is de code that I use to (try to) solve the equations.

restart;

;
q := 0.16021e-18;
k := 0.13865e-22;


NULL;
Ns := 28;
T := 273+27.82;
Isc := 2.07;
Voc := 19.45;
Impp := 1.88;
Vmpp := 15.32;
                           Rsh := 326
dvdi := -1.52;


Vt := n*k*T*Ns/q;

NULL;
f1 := Rs = -dvdi-Vt/(Io*exp(Voc/Vt));
f2 := Io = (Isc-Voc/Rsh)/(exp(Voc/Vt)-1);
                            /Impp Rs + Vmpp\   Impp Rs + Vmpp
   f3 := Impp = Isc - Io exp|--------------| - --------------
                            \      Vt      /        Rsh      

fsolve({f1, f2, f3}, {Io, Rs, n});

Though running this doesn't give me a solution. 

I do have a working extraction though which is the same equations but with other variables: 

restart;

NULL;
q := 0.16021e-18;
k := 0.13865e-22;


NULL;
Ns := 72;
T := 298;
Isc := 8.53;
Voc := 44.9;
Impp := 8.04;
Vmpp := 36.1;
Rsh := 401.934;
dvdi := -.48766;


Vt := n*k*T*Ns/q;

NULL;
f1 := Rs = -dvdi-Vt/(Io*exp(Voc/Vt));
f2 := Io = (Isc-Voc/Rsh)/(exp(Voc/Vt)-1);
f3 := Impp = Isc-Io*(exp((Impp*Rs+Vmpp)/Vt)-1)-(Impp*Rs+Vmpp)/Rsh;

fsolve({f1, f2, f3}, {Io, Rs, n});

I'm am wondering why the first code doesn't give me a solution? I would guess that there is certainly a solution. Also when I slightly increase /  decrease a certain variable it can suddenly give/find a solution.

Could someone clear this out ?

Kind regards, Sven!

Why does the implicit plot return empty?

plots:-implicitplot((x^2+y^2 = 1)^2, x = -3 .. 3, y = -3 .. 3);# plots
   plots:-implicitplot((x^2+y^2-1)^2, x = -3 .. 3, y = -3 .. 3) # empty plot

I kind of work on generat asample from  Adiscret uniform distribution with pdf (P(x)=1/k+1  x=0..k). 
but i couldn't insert the PDF to generate asample is there any way to insert this pdf in maple then generata asample

So I currently have:
with(DifferentialGeometry); with(Tensor);
DGsetup([r, theta], pol);
g1 := evalDG(drdr+r^2d(theta)d(theta))
C1 := Christoffel(g1);
However its coming back saying that g1 is not of metric form, am i missing something? Thanks

Dear Maple users

I am trying to test how well data from a real throw with a ball comply with the usual model, in which the air resistance is proportional to the square of the velocity. I succeeded in solving the ODE system numericallly using the rkf45 method and plottet the solutioncurve (see attached file). I am however unsure how I can retrieve the data from the model in the most convenient way in order to compare them to the data from the real throw. The latter I have as (t, x(t), y(t)) data in three columns in an Excel file. Of course I can import the x og y columns into Maple and create a plot containing both the (x,y) data from Excel and the (x,y) data from the model. The problem is however that even if the (x,y) curves are rather close, if may not be a good model. I need to take into account the time variabel as well! The data from the Excel file contains data for every 1/30 second. What I like is to be able to compute the Root Mean Square of all (x_experiment(t)-x_model(t), y_experiment(t)-y_model(t)) data - or would the Root Mean Square of the (Euclid) distances between the points be better?

Now back to my question on how to retrieve data from the ODE system in the most convenient way. I have read the help page for the dsolve command. There is however several options, that I am unsure about, for example the output option (listprocedure, etc). I hope someone can help. 

NB! Excel data are imported column by column into Maple as n x 1 matrices.

Regards,

Erik V. 

Throw_with_air_resistance_1.mw
 

Say I have three (3d if it matters) plot objects, which I will call A,B,C.

I need to plot A and B on the same graph and C on a different graph.

To plot objects on different graphs I would normally use an array of plots, and to plot objects on the same graph, I would use a set of plots. So what comes natural to me is this:

V:=Array(1..2):

V[1]:={A,B}:
V[2]:=C:

display(V)

However, this results in

Error, (in plots:-display) element 1 of the rtable is not a valid plot structure

 The problem is in the first element V[1] - Maple wants a plot, and not a set of plots, as each element of the array.

Another attempt which fails is the following:
 

display({A,B},C)

Here Maple will only plot {A,B} and ignore C.

I have had limited success with

 
display({A,B}), display(C)

which in fact works for the purpose stated above - it will produce the plots of {A,B} and C side by side.

However, when I try to put the above command within a procedure depending on some parameter, and use the Explore parameter to visualize the plots in dependence of the parameter, this does not work anymore. Maple will not produce any plot and will produce a wall of text within the Explore display.

For istance, 

with(plots); with(plottools)
display(circle([0, 0], 1)), display(circle([0, 0], 1))

Will produce the pictures side by side as desired. But:

P := proc (a)
display(circle([0, 0], 1)), display(circle([0, a], 1))
end proc:
Explore(P(a), parameters = [a = -1 .. 1])

Will result in a wall of text within the Explore window that begins like this:

So, is there a way to produce the plots I need which is compatible with the Explore command for a procedure? Ideally I need the two graphs ({A,B} and C) side by side within the same Explore window so that when I vary the parameters, both plots change accordingly. 

Thanks in advance.

Hi;

I wrote a procedure. It includes two matrices which are H and psi. I highlighted the matrices in the following code.
I saved the file by using the following code. 

save newprocedure, "file.m";

In the other worksheet, I want to call and use these two matrices. 

How can I do?

You can find the following code for details.

procedure.mw

In the other worksheet; I can call one of these matrices, but I can' t call both of them.

restart;
read "C:\\Users\\PC\\Desktop\\file.m";
newprocedure(2);

can maple do a real time update graph by for loop read file data?

i can only think that use for loop and read file and draw a sequence of graph,

but memory will be accumulated to consume

just want to make a dashboard to display a multiple of graphs

How do I save these fonts as my default ones?                                

"Maple Input: Arial 24, Red"

and "2D Output: Arial 18, Blue".

I am using Maple 13.

Thank you!

would like to point to graph then it highlight graph with virtical line

and mark 1 in one of row in one of column in table like data 

just like define feature manually for machine learning but using graph

By default Maple labels vertices 1, 2, ...  and places these numbers within a circle making the position of the vertex.  Can one change the labels to, say, v1, v2, ... and place these outside the circles?  ..................Edgar

Write a program in Maple that solves the recurrence equations given for K[n] and R[n] numerically. Assume that if the recurrence equations return less than half a rabbit or fox, K[n] ≤ 0.5, respectively R[n] ≤ 0.5, at a time n, this means that the rabbits or foxes go extinct. Check that your program reproduces the equilibrium-solution if you start with the initial values K0 = Ke and R0 = Re.

Hi. I have an equation that consists lots of sines and cosines but I'm not sure how to differentiate it with respect to time. Whenever I do, I get zero. How do I communicate to Maple that theta changes with time so that it can perform the operation?

Is there any way to transfer the equation to MATLAB and perform it there by any chance? I don't know MATLAB though.

Thanks in advance.

After doing some calculations, the result includes 20 rows,  3 columns.

but it doesn't appear. How can we see the result?

Please find the following code?

problem.mw

Thanks.

Please describe the step-by-step application of the rules of differentiation which produce this derivative:

diff(a(x)^b(x), x) =        

a(x)^b(x)*((diff(b(x), x))*ln(a(x))+b(x)*(diff(a(x), x))/a(x));