Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

I have the function  and derivate with respect to ν and make the change variable ν=1/t it seems it doesn’t work. I put the derivate of 1/t => -1/t2 by hand  (could it be done by “dchange” the hole transformation ?)

I want to approximate the value of the integral. It seems that the solution of the equation and plot in 2 situations for low-frequency ν < 1014  and for high frequency so  when the exponential is dominated.

Thus plot the whole function E2 in the two situations. Could it be done with a series?

For value h := 6.62607015*10^(-34); c := 299792458; T := 273 + 24; k := 1.380649*10^(-23);

ec := 1.602176634*10^(-19); ν1 :=1012 ; ν2 := 1017 ;Tq := 1.765358264*10^(-19);

Could it be merged E2 into one plot for ν = 1012 .. 1017

PPh1.mw

Loop is not executing all values just considerinng 1st value of tau0 =0.3.

Also how to plot a 2D graph from the loop result

Attaching sheet with questions in the sheet:
for_loop_question_rec.mw

Dear Maple user

I want to add caption for all four graphs with a,b,c,d at the bottom centre of each graph that should be arrange in 2X2 array and the array bottom caption as Figure 6, also i want to save the output of the array graphs in desktop with jpeg format. sample graph i have uploaded.

restart:
with(plots):
A1:= plot(sin(x), x = -Pi .. Pi,title = "Graph at M^2=1",caption = "Fig a"):# This caption is at the centre bottom of first graph and the title of A1 is M*M (M^2)should be display
A2:= plot(cos(x), x = -Pi .. Pi,caption = "Fig b"):# This caption is at the centre bottom of second graph
A3 := plot3d(1.5^x*sin(y), x = -3 .. 3, y = -3 .. 3,caption = "Fig c"):# This caption is at the centre bottom of Third graph
A4 := plot3d(1.3^x*sin(y), x = -1 .. 2*Pi, y = 0 .. Pi,caption = "Fig d"):# This caption is at the centre bottom of forth graph
display(Array(1 .. 2, 1 .. 2, [[A1, A2], [A3, A4]]), aligncolumns = [1],caption = "Fig 6"):# This caption at the bottom centre of array graphs 

I cannot remember that this was an issue in Maple 6/9/11, so it must have changed later on up to 22.

The following limit fails to execute

restart;
1/(r_S^5*(_C2*r_S^4 + _C2*r_S^3 + _C2*r_S^2 + f[3](0)*r_S + f[4](0)));
limit(%, f[4](0) = infinity);

It fails to calculate the limit with result as zero.

Thanks

Bernoulli first order ode has form as show in wikipedia  and also on Maple own site as

Notice that it is P(x)*y above and not P(x)* y^(-1) so the y(x) must be linear in that term.   But when I give Maple this ode

ode:=diff(y(x),x) + x*y(x)^(-1)= y(x)^(-1);

Which is clearly not of the form above, it solves it as Bernoulli.  In the above ode, P(x) is x and Q(x) is 1 and n is -1.

The ode advisor correctly said it is separable. But trace shows it used Bernoulli. Also when asking it to solve it as Bernoulli, it does.

What Am I missing here?  Is it not wrong for Maple to use Bernoulli method on this ode which is not Bernoulli?

Worksheet below

interface(version);

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1805 and is the same as the version installed in this computer, created 2024, September 3, 11:35 hours Pacific Time.`

libname;

"C:\Users\Owner\maple\toolbox\2024\Physics Updates\lib", "C:\Program Files\Maple 2024\lib"

restart;

ode:=diff(y(x),x) + x*y(x)^(-1)= y(x)^(-1);
IC:=y(1) = 0;
DEtools:-odeadvisor(ode);

diff(y(x), x)+x/y(x) = 1/y(x)

y(1) = 0

[_separable]

infolevel[dsolve]:=5;

5

dsolve(ode,y(x));  #why this says it solved it as Bernoulli ?

Methods for first order ODEs:

--- Trying classification methods ---

trying a quadrature

trying 1st order linear

trying Bernoulli

<- Bernoulli successful

y(x) = (-x^2+c__1+2*x)^(1/2), y(x) = -(-x^2+c__1+2*x)^(1/2)

dsolve(ode,y(x),[Bernoulli])

Classification methods on request

Methods to be used are: [Bernoulli]

----------------------------

* Tackling ODE using method: Bernoulli

--- Trying classification methods ---

trying Bernoulli

<- Bernoulli successful

y(x) = (-x^2+c__1+2*x)^(1/2), y(x) = -(-x^2+c__1+2*x)^(1/2)

 

 

Download why_this_ode_bernullli_sept_15_2024.mw

I don't know how make my graph be beter for real part and imaginary part and abs part which part how work with parameter can any one explain on this example?

G.mw

I've recently started to move my Maple software development from pure Maple to Visual Studio Code with GitHub. Previous code attachments in workbooks are now moved to its own folders, and fetched by the $include instruction.

The approach works quite well, but I have experienced a strange effect. While the Maple workbook itself is in the local GitHub folder, I do experience that when documents within the Maple workbook, after a while the code is fetched from the backup location. This doesn't work, as the $included files can't be found there. Only way is to close the workbook, and open it again.

First image shows location of Maple workbook, second location of document (backup position, error), third location of document after reopening workbook (working).

i did two case of this equation and odetest is worked good but in this case the odetest is not worked well anyone can determine what is mistake ?

F_P_Correct_case_three.mw

Dear Maple user I am facing error while running the codes  to plot the graph for two data sets .

I am attaching the files.

Error_in_Display_1.mw

HTR.mw

In above problem, Additionally How to  plot  heat transfer rate  Q versus L^2  for distinct porosity parmeters(Sh) , using  heat transfer rate formula, Q = (q*L)/(k*A*T[b])=theta'(1).

using  [Sh = 0.1, L^2 = 0.1, Nr =0 .1, Ha =0 .1, Pe = 0.1],  [Sh = 0.3, L^2 = 0.3, Nr = 0.1, Ha = 0.1, Pe =0 .1],   [Sh = 0.5, L^2 =0 .5, Nr =0 .1, Ha = 0.1, Pe =0 .1].

I get my on results but the results are not the same please help me if i did any mistake in my code

 

symmetry_PDESYS_3_time_fraction[1].mw

Hello everyone 

Any one can help to plot a figure as follows 

" A cross section of three colored basins of attraction on an (x, y)

plane at z = 0 and w = 0 for a = 2.48 and b = 0.5. Basins in green, red, and cyan leads to a strange attractor, a limit cycle, and a line equilibrium, 

respectively. The yellow leads to unbounded orbits. " Where the system 

xdot=y 

ydot=z

zdot=w

wdot=-az-bw-y-xy. 

and range of x=[-6,6] and y=[-3,6]. 

Hi everyone, is there any source of Maple competitions? Or related questions? I have a hard time finding books on this subject. I am very interested in Maple and hope to improve my Maple programming skills. In addition to frequently browsing this website, I encounter problems on the Internet sporadically, so I think starting with competition questions will be a quick way to improve.

can someone help me curve fitting these parameeters...i only got 1 for all of this 90As4.mw

restart

with(Statistics)with(plots)with(Optimization)with(LinearAlgebra)

E[1] := 126*10^9E[2] := 11*10^9G[12] := 6.6*10^9G_0__12 := 10.1*10^9nu[12] := .28E_0__2 := 15.5*10^9

true_strain := [0, .406915, .710106, .989362, 1.28457, 1.53989, 1.86702, 2.21011, 2.625, 2.99202]; true_stress := [0, 46.0227*10^6, 81.8182*10^6, 109.091*10^6, 138.068*10^6, 163.636*10^6, 194.318*10^6, 219.886*10^6, 248.864*10^6, 267.614*10^6]; epsilon_dot := 10^(-4)

sigma_t := map(proc (epsilon) options operator, arrow; E[instantaneous]*(1-lambda[90*deg]*epsilon*(sum(P[i], i = 1 .. 10)-(sum(P[i]*exp(lambda[i]*epsilon/epsilon_dot), i = 1 .. 10)))/epsilon_dot)*epsilon end proc, true_strain)

``

obj := sum((sigma_t[i]-true_stress[i])^2, i = 1 .. 10)

indets(obj, name)

{E[instantaneous], P[1], P[2], P[3], P[4], P[5], P[6], P[7], P[8], P[9], P[10], lambda[1], lambda[2], lambda[3], lambda[4], lambda[5], lambda[6], lambda[7], lambda[8], lambda[9], lambda[10], lambda[90*deg]}

(1)

Optimization[Interactive](obj)

The solution was obtained with the following warning:
  no iterations performed as initial point satisfies first-order conditions

 

[Float(infinity), [E[instantaneous] = HFloat(1.0), P[1] = HFloat(1.0), P[2] = HFloat(1.0), P[3] = HFloat(1.0), P[4] = HFloat(1.0), P[5] = HFloat(1.0), P[6] = HFloat(1.0), P[7] = HFloat(1.0), P[8] = HFloat(1.0), P[9] = HFloat(1.0), P[10] = HFloat(1.0), lambda[1] = HFloat(1.0), lambda[2] = HFloat(1.0), lambda[3] = HFloat(1.0), lambda[4] = HFloat(1.0), lambda[5] = HFloat(1.0), lambda[6] = HFloat(1.0), lambda[7] = HFloat(1.0), lambda[8] = HFloat(1.0), lambda[9] = HFloat(1.0), lambda[10] = HFloat(1.0), lambda[90*deg] = HFloat(1.0)]]

(2)
 

NULL

Download 90As4.mw

I apologize for putting the equations in image format, but I thought that this way the community could better understand how to interpret the equations.

Below are 6 letters whose solution must be developed step by step so that the periodic extension of each one can then be done. I can solve all the letters by hand (solving in the notebook), but my big question is, how can I do the commands in Maple step by step so that I can solve them as if I were doing them by hand (look like in my notebool)? I need to check step by step. I would be extremely grateful for the help of any of you.

second part

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