Please how do I solve the above 2nd order differential equation (F and K are constants)?

I have the following boundary conditions:

Many thanks!

Hi everyone,

I'm trying to solve the following equation and unfortunately I get this error ( Error, (in Engine:-Dispatch) invalid subscript selector ) each time I try. Could you please help me??

I will be thankful for your great help.

solve(m*exp(-(m-1)*t_ij)*d²-θ+θ*t_ij-θ*(Σ(t_kj, k = 1 .. c))-m*η*(1-exp(-t_ij))^(m-1) = 0, t_ij)

Hello !!

I want to replace the word "assuming" with another word. I tried to write:

> as:=assuming;

> alias(as=assuming);

> `&as`:=proc(a,b) a assuming b; end;

The first two methods are not allowed. The last one doesn't work like "assuming".

Is there any solution to this problem ?

How does one 3D plot the simple complex exponential e^I2pift or cos(2pift)+I*sin(2pift)  where f is freqency and t is time.  It shoud display a spiral aroung the time axis.

This may be a trivial question, but does this factor fully with the newer versions of Maple, say at 900 digits?

Digits:=900;

rho_poly := -2201506283520*rho^32+(-17612050268160+104204630753280*I)*rho^31+(2237195146493952+737798139150336*I)*rho^30+(14065203494780928-29153528496783360*I)*rho^29+(-260893325886750720-161432056834818048*I)*rho^28+(-1240991775275876352+1727517243589263360*I)*rho^27+(8952004373272068096+6696323263091441664*I)*rho^26+(25553042370906292224-37948239682297921536*I)*rho^25+(-135024511500569280512-65293199430849134592*I)*rho^24+(-79740262928225402880+401487130320847241216*I)*rho^23+(956745211126674882560-164797793704574713856*I)*rho^22+(-1213375867282228772864-1655554058430246551552*I)*rho^21+(-1483956336776821211136+3604946201834409820160*I)*rho^20+(6525094787202650144768-1597915397190007586816*I)*rho^19+(-8575469412912592879616-6168391294117580865536*I)*rho^18+(2408139380338842796032+15004449784317106323456*I)*rho^17+(10583091471310114717696-17047513330720373194752*I)*rho^16+(-22619716982813548707840+8898637295768494915584*I)*rho^15+(26538067620972845277184+5129530051326543351808*I)*rho^14+(-21415800164460070789120-17268159356969925234688*I)*rho^13+(11916012071577094946816+22601135173030541677568*I)*rho^12+(-3551246770922037813248-21229478915196610975744*I)*rho^11+(-977434486760953073664+16249214903618313346048*I)*rho^10+(1977414870691507931136-10721551032564274826240*I)*rho^9+(-1197394212949208115968+6172794574205050632192*I)*rho^8+(280273257275327368320-2996290081120136529792*I)*rho^7+(108849195761508531648+1152454823926345101504*I)*rho^6+(-119736267114490955904-327757949185254534784*I)*rho^5+(49149411853848597568+63563541902968683712*I)*rho^4+(-11524495997215059744-7307364351434838944*I)*rho^3+(1585189353379709888+299568910286253408*I)*rho^2+(-116032795768295808+25487628220230528*I)*rho+3299863116538269-2454681763039104*I;;

Good Day Everybody, I m new to maple and would like to translate the following for loop from Matlab to Maple. The FromMatlab Translater didnt work for this expression related to the matrix Q, A, B D and A1. Any help would be greatly appreciated.

Related Matlab Code:

...

Q(3,3)=2*Q(3,3);

 for i=1:length(R)

    T(1,1)=cos(R(i))^2; 

    T(2,2)=cos(R(i))^2; 

    T(1,2)=sin(R(i))^2; 

    T(2,1)=sin(R(i))^2; 

    T(3,1)=-sin(R(i))*cos(R(i)); 

    T(3,2)=sin(R(i))*cos(R(i)); 

    T(1,3)=2*sin(R(i))*cos(R(i)); 

    T(2,3)=-2*sin(R(i))*cos(R(i)); 

    T(3,3)=cos(R(i))^2-sin(R(i))^2;

    T1(1,1)=cos(R(i)); 

    T1(1,2)=-sin(R(i)); 

    T1(2,1)=sin(R(i)); 

    T1(2,2)=cos(R(i));

    Qk(:,:,i)=inv(T)*Q*T; 

    Qk(:,3,i)=Qk(:,3,i)/2; 

    Qk1(:,:,i)=inv(T1)*Q1*T1;

    A=A+Qk(:,:,i)*(h(i+1)-h(i)); 

    B=B+.5*Qk(:,:,i)*(h(i+1)^2-h(i)^2); 

    D=D+1/3*Qk(:,:,i)*(h(i+1)^3-h(i)^3); 

    A1=A1+Qk1(:,:,i)*(h(i+1)-h(i));

end

Thanks a lot in advance.

So I installed copied DirectSearch.hdp and DirectSearch.mla into my Maple2015\lib directory and the program works (all the functions are there) but I cant get help menu by querying ?DirectSearch.

I'm running win7 64bit btw

so under

?hdb

i put this into maple:

HelpTools:-Database:-ConvertAll();

but i get error....

"Converting C:\\Program Files\\Maple 2015\\lib\\DirectSearch.hdb to C:\\Program Files\\Maple 2015\\lib\\DirectSearch.help"
Warning, .hdb help databases are deprecated, 'C:\Program Files\Maple 2015\lib\DirectSearch.hdb' will not be used, see ?HelpTools,Migrate help page for more information
Error, (in HelpTools:-HelpCallUI) cannot create help database: 'unable to open database file'

any clue?

ps I asked the same question for M18 but I managed to get the help to work in that instance.

http://www.mapleprimes.com/questions/204423-Help-Build-For-GlobalSearch-Package

(i also copied DirectSearch.hdp and DirectSearch.mla to Maple2015\bin.X86_64_WINDOWS directory but no joy, there is no .help file created in either bin or lib directories)

(1,1,0), (0,0,0), (0,1,0)

1-0, 1-0, 0-0
0-0, 1-0, 0-0

with(LinearAlgebra):
m := Matrix([[i, j, k], [1, 1, 0], [0, 1, 0]]);
Determinant(m);
1*z = 0;

plot3d(z=0, x=0..1, z=0..1); #this can not plot

0*(x-0) + 0*(y-0) + 1*(z-0) = 0

would like to draw 3d rectangle in 3d plot with one formula

a system of monomials, which has 5 equations for 5 variables , have more than one solutions,

first solution is my wanted solution,

how to eliminate other unwanted solutions?

whether

1. add more equations to eliminate unwanted solutions? how to do?

or

2. edit existing system to eliminate unwanted solutions? how to do?

    a.  add extra terms to some equations?

what is the cause that make it having more than one solutions?

can this reason help to edit existing system?

i succeed with adding extra equation，a1+a2+a3+a4+a5-(6+s) =0  in 3 variables case, it calculate very fast within 1 second.

but when calculating 5 variables, it evaluating a very very long time, what is the problem

without extra equation a1+a2+a3+a4+a5+a6+a7-(1+2+3+4+5+s), it get result within 1 second, but after adding this extra equation, it is like dead loop,

my surface computer run with large fans noise and very hot.

restart;
H := subs(p=diff(f(q,P,t), q), 1/(2*m)*p^2 + 1/2*m*w^2*q^2) = -diff(f(q,P,t), t);
H:=subs( f(q,P,t) = f1(q) + f2(t), H);
sol:=dsolve({rhs(H)=E,lhs(H)=E});
S:=rhs(sol[1][1]+sol[1][2]);
subs(m=1, diff(S,q));
p := (E, w) -> -(1/2)*sqrt(-q^2*w^2+2*E)+(1/2)*q^2*w^2/sqrt(-q^2*w^2+2*E)-E*(sqrt(w^2)/sqrt(-q^2*w^2+2*E)+sqrt(w^2)*q^2*w^2/(-q^2*w^2+2*E)^(3/2))/(sqrt(w^2)*(1+w^2*q^2/(-q^2*w^2+2*E)));
lst := [seq(p((1/2)*E, w), E=0..5),seq(-p((1/2)*E, w), E=0 .. 5)]:
plot(lst, w= -3*Pi..3*Pi, color = black, numpoints=1000);

Q is the new coordinate which is diff(S,E)

t0 is the time when argument of solve(subs(m=1, diff(S,E))=0, t) vanish
initialq := solve(solve(subs(m=1, diff(S,E))=0, t)=0, q);

after find the initial value, how to plot with new coordinate?

dsolve({H, q=0}, f(q,P,t));

i try another way to do

restart;
H := subs(p=diff(f(q,P,t), q), 1/(2*m)*p^2 + 1/2*m*w^2*q^2) = -diff(f(q,P,t), t);
H:=subs( f(q,P,t) = f1(q) + f2(t), H);
sol:=dsolve({rhs(H)=E,lhs(H)=E});
S:=rhs(sol[1][1]+sol[1][2]);
p2 := subs(m=1, diff(S,q));

initialq := solve(solve(subs(m=1, diff(S,E))=0, t)=0, q);

H := subs(p=p2, 1/(2*m)*p^2 + 1/2*m*w^2*q^2) = -diff(f(t), t);
H := subs(w=theta(t), H);
sol := dsolve({H, q=0}, numeric, range = 0 .. 30);
odeplot(sol, [t, theta(t)], refine = 2);

Error, (in dsolve/numeric/process_input) invalid specification of initial conditions, got q = 0

restart;
H := subs(p=diff(f(q,P,t), q), 1/(2*m)*p^2 + 1/2*m*w^2*q^2) = -diff(f(q,P,t), t);
H:=subs( f(q,P,t) = f1(q) + f2(t), H);
sol:=dsolve({rhs(H)=E,lhs(H)=E});
S:=rhs(sol[1][1]+sol[1][2]);
subs(m=1, diff(S,q));
p := (E, theta) -> -(1/2)*sqrt(-q^2*w^2+2*E)+(1/2)*q^2*w^2/sqrt(-q^2*w^2+2*E)-E*(sqrt(w^2)/sqrt(-q^2*w^2+2*E)+sqrt(w^2)*q^2*w^2/(-q^2*w^2+2*E)^(3/2))/(sqrt(w^2)*(1+w^2*q^2/(-q^2*w^2+2*E)));
lst := [seq(p((1/2)*E, theta), E=0..5),seq(-p((1/2)*E, theta), E=0 .. 5)]:
plot(lst, theta = -3*Pi..3*Pi, color = black, numpoints=1000);

i plot it circle in circle, should i substitute a value to q before plot?

i guess q is velocity, is it?

why substitute E with 1/2*E?

subs(q=1, subs(m=1, diff(S,q)));
p := (E, w) -> -(1/2)*sqrt(-w^2+2*E)+(1/2)*w^2/sqrt(-w^2+2*E)-E*(sqrt(w^2)/sqrt(-w^2+2*E)+sqrt(w^2)*w^2/(-w^2+2*E)^(3/2))/(sqrt(w^2)*(1+w^2/(-w^2+2*E)));
lst := [seq(p((1/2)*E, w), E=1..5),seq(-p((1/2)*E, w), E=1 .. 5)]:
plot(lst, w = -3*Pi..3*Pi, color = black, numpoints=1000);

Hi all,

I deal with the following ODE system which present a singularity when v(x)=0. I want to inject the condition "if v(x)=0 then u(x)=0" as may be a solution to avoid this singularity. If someone could help me to do that. Thanks.

SYS:={u(x)*sqrt(v(x))-diff(v(x),x)*x-2*v(x)=0,2*u(x)*v(x)*diff(v(x),x,x)-u(x)*(diff(v(x),x))^2+2*diff(u(x),x)*v(x)*diff(v(x),x)+v(x)*sqrt(v(x))*(2*x*diff(u(x),x)+6*u(x))=0};

ICS := { u(-2) = 4,   v(-2) = 4, (D(v))(-2) = 0 };
p:= dsolve( SYS union ICS,method=rkf45_dae,numeric,output=listprocedure);
solp := plots[odeplot](p, [[x, u(x)],[x, v(x)]], x = -5 .. 0);
plots[display](solp);

Hello, 

Im a chemical engineer student with very little knowledge of Maple and its possibilities (which seem endless). I have very little coding experience, even though i do write in LaTeX (which i suppose is referred to as pseudo-code). 

I figured, that as a student, i often run into the same number x problems, that each can be solved in x different ways. Since Maple is so good with units and calculations, aswell as defining variables. I could make some very smart notes, which would allow me to solve different (mostly simple) problems in a very easy and fast manner. 

Now, since i dont know much about Maple, i want to seek som help. 

How do i proceed to make such a document / multiple documents for my purpose? My first idea was to simply create a bunch of different variables defined to a given input, and then simply change the variables as i get a new problem. But i figured that there must be smarter and more neet ways to make this. 

Let me know what you think. 

Sincerely, Mikkel.

Hi,

I am working on a Windows machine. In older Maple versions, decreasing the font size for the screen display (via zoom factor) also decreased the font size for the printout. But now the printout comes with a pretty large font size and does not change when using the zoom factor. It practically makes no sense anymore to print. How can I decrease the fonts for the printout to my liking?

Thanks.

heide

I run the following working maplet:

Where "muutujad" is a procedure I defined and which returns the three inputs in the form [TF1,TF2,TF3].

It works fine, but if I insert "theta" as input, it of course stays in the string form, not Θ. Even if I copy the symbol and paste it in the textfied, it doesn't accept the symbol. Is there any way I can convert the text input to actual symbol?