it took a while to track this. When I run these 3 ode's in this sequence, Maple gives

**Error, (in Engine:-Dispatch) too many levels of recursion**

and it has to be this sequence. I also found I might have to run the code 2 or 3 times to get this error if it does not show first time.

Will show a movie below also.

Here is the code

restart;
ode1:=cos(y(x)) - x*sin(y(x))*diff(y(x), x) = sec(x)^2:
ode2:=y(x)*sin(x/y(x)) + x*cos(x/y(x)) - 1 + (x*sin(x/y(x)) - x^2*cos(x/y(x))/y(x))*diff(y(x), x) = 0:
ode3:=x/(x^2 + y(x)^2) + y(x)/x^2 + (y(x)/(x^2 + y(x)^2) - 1/x)*diff(y(x), x) = 0:
func:=y(x);
the_ic:={};
the_time_limit:=60;
advisor:=timelimit(the_time_limit,DEtools:-odeadvisor(ode1)):
solution_by_CAS := timelimit(the_time_limit,:-dsolve([ode1,y(0)=0],func,singsol=all)):
result_of_ode_test := timelimit(the_time_limit,:-odetest~([solution_by_CAS],ode1)):
advisor:=timelimit(the_time_limit,DEtools:-odeadvisor(ode2)):
solution_by_CAS := timelimit(the_time_limit,:-dsolve([ode2,y(0)=0],func,singsol=all)):
result_of_ode_test := timelimit(the_time_limit,:-odetest~([solution_by_CAS],ode2)):
advisor:=timelimit(the_time_limit,DEtools:-odeadvisor(ode3)):
solution_by_CAS := timelimit(the_time_limit,:-dsolve([ode3,y(1)=0],func,singsol=all)):
result_of_ode_test := timelimit(the_time_limit,:-odetest~([solution_by_CAS],ode3));

And here is a movie (this time it happend on second run) sometimes it happens on first run. so it is random.

Maple 2020.1

Why does it happen and is there a work around?

Noticed few errors generated on some ode's. I do not know if these are expected or known, I thought may be someone might want to check them.

restart;
ode1:=(a^2*x+y(x)*(x^2-y(x)^2))*diff(y(x),x)+x*(x^2-y(x)^2) = a^2*y(x);
ode2:=x^7*y(x)^2*diff(y(x),x)^3+(1-3*x^6*y(x)^3)*diff(y(x),x)^2+3*x^5*y(x)^4*diff(y(x),x)-x^4*y(x)^5 = 0;
ode3:=diff(y(x),x)^4+x*diff(y(x),x)-3*y(x) = 0;

sol:=timelimit(60,:-dsolve(ode1,y(x))):

Error, (in dsolve) numeric exception: division by zero

sol:=timelimit(60,:-dsolve(ode2,y(x))):
timelimit(60,:-odetest([sol][5],ode2))

Error, (in IntegrationTools:-Indefinite:-AlgebraicFunction) argument is not an algebraic

sol:=timelimit(60,:-dsolve(ode3,y(x))):
timelimit(60,:-odetest(sol[1],ode3));
timelimit(60,:-odetest(sol[2],ode3))

Error, (in odetest) received not an ODE w.r.t x(_T)

Error, (in odetest) received not an ODE w.r.t y(_T)

This last one is only due to how the solution is given. So I do not think it is a real problem.

Maple** 2020.1**, Physics **708**

windows 10

Maple Worksheet - Error

Failed to load the worksheet **/maplenet/convert/check.mw **.

Download check.mw

Dear All.

I hope we are all staying safe.

Please I want to solve Sine Gordon Equation using a numerical method I constructed (non-classical), I need to compare the result of the method with the exact solution to generate the errors. However, since the exact solution has two variables, x, and t, I really don't know how to accommodate the two in my coding.

Can someone be of help in this regard?

Thank you and kind regards

Download Discretization_of_Sine_Gordon_Equation.mw

Download Sine_Gordon_Implementation_Trial.mw

Hi there,

Can someone explain to me why is it happening? If smaller equal than coloured well, if smaller then just the equal line appears. Why?

with(plots);
dm1 := .23; pm12 := .7; dm12 := .23;
inequal(pm1*(dm12+am21)-pm12*(dm1+am21) <= 0, pm1 = 0 .. 1, am21 = 0 .. 1, color = "Nautical 1");

inequal(pm1*(dm12+am21)-pm12*(dm1+am21) < 0, pm1 = 0 .. 1, am21 = 0 .. 1, color = "Nautical 1")

Thank you!

Etude d'un cas particulier
a := 5: b := 7:
k := 9:
A := [a, 0]: B := [0, b]: #A et B fixes
P := [t, 0]: Q := [0, k/t]:#P et Q 2 points mobiles
cir := -a*x-b*y+x^2+y^2 = 0:
sol := solve(subs(y = 5, cir), x):
cen := [solve(diff(cir, x)), solve(diff(cir, y))]:
x0 := sol[1]: y0 := 5:
M := [x0, y0]:
R := sqrt(cen[1]^2+cen[2]^2):
beta := arctan(diff(solve(EQ(M, cen), y), x)):
Recherche des valeurs de t pour que les 2 droites soient perpendiculaires
eq := t^2*(y0-b)+t*(a*b-a*y0+b*x0-k)-x0*(a*b-k) = 0;
sol := solve(eq, t);
t := sol[1]; tp := sol[2];
P1 := [t, 0]; Q1 := [0, k/t];
PQ1 := simplify(x*(-a*b+b*t+k)+y*t*(t-a)-t*(-a*b+b*t+k)) = 0:#1ere tangente
PQ2 := simplify(x*(-a*b+b*tp+k)+y*tp*(tp-a)-tp*(-a*b+b*tp+k)) = 0:#2ième tangente
P2 := [tp, 0]; Q2 := [0, k/tp];
CIR := implicitplot(cir, x = -4 .. 8, y = -4 .. 12, color = red);
Fig := proc (alpha) local Dr1, DR1, Dr2, DR2, N, u0, v0, Po, t, tp, sol; global a, b, k, cen, R; u0 := cen[1]+R*cos(alpha); v0 := cen[2]+R*sin(alpha); N := [u0, v0]; sol := solve(t^2*(v0-b)+t*(b*u0-a*v0+a*b-k)-u0*(a*b-k) = 0, t); t := sol[1]; tp := sol[2]; Dr1 := simplify(x*(-a*b+b*t+k)+y*t*(t-a)-t*(-a*b+b*t+k)) = 0; DR1 := implicitplot(Dr1, x = -4 .. 8, y = -4 .. 12, color = brown); Dr2 := simplify(x*(-a*b+b*tp+k)+y*tp*(tp-a)-tp*(-a*b+b*tp+k)) = 0; DR2 := implicitplot(Dr2, x = -4 .. 8, y = -4 .. 12, color = pink); Po := pointplot([N[]], symbol = solidcircle, color = [black], symbolsize = 8); display([Po, DR1, DR2]) end proc;
DrPQ1 := implicitplot(PQ1, x = -4 .. 22, y = -4 .. 12, color = blue);
DrPQ2 := implicitplot(PQ2, x = -4 .. 22, y = -4 .. 12, color = blue);
Points := pointplot([A[], B[], M[], P1[], P2[], Q1[], Q2[], cen[]], symbol = solidcircle, color = [green], symbolsize = 10);
T := plots:-textplot([[A[], "A"], [B[], "B"], [M[], "M"], [P1[], "P1"], [P2[], "P2"], [Q1[], "Q1"], [Q2[], "Q2"], [cen[], "cen"]], font = [times, 10], align = {below, left});
n := 19;
display([seq(Fig(2*i*Pi/n), i = 0 .. n), Fig(beta), CIR, DrPQ1, DrPQ2, Points, T], scaling = constrained, size = [500, 500]);
I would find out the focus of the ellipse. Thank you.

When I type "with(combinat)" in Maple Linux, I got the following erros message:

"Error, invalid input: with expects its 1st argument, pname, to be of type {`module`, package}, but received combinat"

So how to make it work?

Many thanks.

Error, (in Compiler:-Setup) unable to write to initialization file, C:\Program Files\Maple 2020\bin.X86_64_WINDOWS/launch.ini, possibly due to insufficient permissions

NULL;

when choose bat file

but i see sufficient permission

any w should i s

choose a particular compiler or even visual studio i have in my system

where can i find if anything else

Hello,

I try import a big Excel file with the first row as column labels for performing statistical etc.

I use this command :

data := Import(FileTools:-JoinPath(["d:", "directory", "subset2.xlsx"], platform = "windows"))

i need a dataframe for performing statistical with column label as first row, but i have this error :

Error, (in Import) invalid input: MatrixToDataFrame uses a 3rd argument, columns, which is missing

I can not understand what is this error...so, what i can do ?

Thanks, regards

Hi experts

with(plots):

#epsilon:=5*Pi/2:

gammaa:=0.4:

gammao:=0.1:

gammab:=0.002:

omegab:=100:

X:=60:

Omega:=6*Pi:

g:=10:

sigmag:=5*gammaa:

a:=1/(sigmag*sqrt(2*Pi)):

#deltao:=1:

D7:=evalf(a*int(g*Omega*(gammao/2-I*Delta)*exp(-0.5*((Delta-deltao)/sigmag)^2)/(gammao^2/4+Delta^2),Delta=-infinity..infinity)):

D8:=evalf(0.5*a*int(g^2*gammao*exp(-0.5*((Delta-deltao)/sigmag)^2)/(gammao^2/4+Delta^2), Delta=-infinity..infinity)):

D9:=evalf(a*int(g^2*Delta*exp(-0.5*((Delta-deltao)/sigmag)^2)/(gammao^2/4+Delta^2), Delta=-infinity..infinity)):

b1 := (deltao-2*X^2*omegab*Y/(gammab^2+omegab^2)-D9)^2:

f:=Y*((gammaa+D8)^2+(b1))=Im(D7)^2+(epsilon-Re(D7))^2:

#P1:=implicitplot(f,deltao=-70..50,Y=0..1,numpoints=100,axes=boxed,thickness=2,color=black,font=[1,1,20],tickmarks=[4, 3],linestyle=1);

implicitplot3d(f,Y = 0 .. 1,deltao=-40..40,epsilon=0..0.4,numpoints=100,labels=[Y,deltao,E],tickmarks=[3,3,3], style = surface, color = "Niagara Azure");

The above code to plot the implicitplot3d ,

first the figures are not smooth

second thing is how to make contourplot at epsilon= 5*Pi/2.

I appreciated any comments