MaplePrimes Questions

Is there a way to play animations in maplets?

I can send an animation to a plotter, but don't know how to play it.  

Thanks, Rollie

Can anyone help me to transform a system of ODE into a power series solution. The system of ODE is as follows:

diff(f(eta), eta, eta, eta)+(diff(f(eta), eta, eta))*f(eta)+1 - (diff(f(eta), eta))^2=0

f(eta)*(diff(theta(eta), eta))+(1/Pr)*diff(theta(eta), eta, eta)=0

where Pr is the prendtl no.

The contents of the "list of list" are hidden... I want to display them in the worksheet without double cliking them to open them... what shall I do? Thank you.

I have a linear space spanned by the column vectors of:

I want to know its exact intersection of the first quadrant in 16 dimensional space (meaning Sum(a[i]*e[i]),i=1..16), how could I accomplish it? The output could possibly be the vectors defining the convex cone in higher dimensional space...

 

 

I have an ipad air 16G running ios 7.0.4 and downloaded the MaplePlayer APP.  t seems to crash on several of the routines for example, "Approximaing Sphere" and "Linear System Tutor". The app was last updated in 2011.  Do you have plans to any upgrades plan in the near future?

I want to know which other maple in-built function does the same thing as fsolve and LinearSolve. I can use both to solve systems of equations either by passing the equations directly to fsolve or deciding to generate matrix to be used in LinearSolve while still getting the same result. So, i'm using this medium to ask if there are/is other inbuilt function that does the same/similar thing as the two.

I am using Maple 16, and trying to display several 3d plots simultaneously in a maplet (e.g. a line and a plane, etc.).  Whenever I use the "display" command the Plotter gives me 2-d axes.  

How can I get the display command to work in Maplets?

For example:

returns the axes in a plane, whereas

returns two surfaces (here the text fields are functions of x and y).

Thanks for any help you can give,

Rollie

hello,

I'm trying to solve the equation of a form like,

diff(eta(tau), tau, tau)+(8/(4*tau^2+1)-32/(4*tau^2+1)^2)*eta(tau) = 0,

when I'm doing solve DE, I get a solution as:=

eta(tau) = _C1*sqrt(4*tau^2+1)*LegendreP((1/2*I)*sqrt(7)-1/2, I*sqrt(7), (2*I)*tau)+_C2*sqrt(4*tau^2+1)*LegendreQ((1/2*I)*sqrt(7)-1/2, I*sqrt(7), (2*I)*tau

which is combination of Legendre Polynomials with imaginary arguments,May I change this form,

How can I plot this solution on real plane, as this is imaginary,

Is the only option remaining NUMERIC PLOT??

Is there a better way to express the sign of a variable that will eventually hold a numeric value?

Up to this point, I have been using x/abs(x) (i.e. x/abs(x)) to represent the numeric sign of a variable. I can later manipulate, substitute, and evaluate any expression involving x/abs(x) without difficulty. For example:
> eval(x/abs(x), [x = -1]);
 -1

The problem is that it's inconvenient when the numeric value is identically zero:
> eval(x/abs(x), [x = 0]);
 Error, numeric exception: division by zero

Using a floating point zero works fine, but is not always practical:
> eval(x/abs(x), [x = 0.]);
 Float(undefined)

Now, the obvious tool here, sign(x), evaluates without complaint:
> sign(0);
 1

The problem with sign is that I cannot incorporate it into an expression that can be freely used later. For, the following produces an unexpected result:
> eval(sign(x), x = -1);
 1

Constructing the expression using layers of quotes don't help:
> expr := 200*' 'sign(x)' ';
 200 'sign(x)'

Simple uses of eval work fine:
> expr;
 200 sign(x)

> eval(expr, [x = -1]);
 -200

However, substitution with that expression using subs or eval doesn't produce the expected result:
> eval(a*b, [a = expr]);
 200 sign(x) b
> eval(%, [x = -1]);
 200 b

This also doesn't produce the expected result:
> subs(a = expr, a*b);
 200 sign(x) b
> eval(%, [x = -1]);
 200 b

I realize that this question might collapse into "How do I prevent a function from evaluating prematurely? " but cannot find any search terms that yield useful results.

sign_of_a_thing.mw

Up to Maple Help, the relatively new command SolveTools[Engine] with the
allsolutions option returns parameterized solutions for non-algebraic equations which may have infinitely many solutions. The question arises: how to extract these?
For example,
sol := SolveTools:-Engine({tan(x) = x}, [x], allsolutions);
[{x = RootOf(-tan(_Z)+_Z)}]
I want to extract the third positive solution (by its value), trying
evalf(allvalues(sol));
[{x = -4.493409458}], [{x = 0.}]
Is it possible at all?

Hello experts..

The following is the IVP:

restart:Digits:=14:t0:=0.0:tN:=5000.0: N1:=5000;th:=evalf((tN-t0)/N1):

dsys1 :=diff(y(t),t)=y(t)*((1-y(t)/3-epsilon)-0.8*y(t)/(y(t)^2+0.5^2));

var:={y(t)}:ini1:=y(0)=0.5:

dsol1 :=dsolve({dsys1,ini1},var,numeric, output=listprocedure, abserr=1e-9, relerr=1e-8,range=0..1);

dsolu:=subs(dsol1,y(t)):

t1:=array(0..N1,[]):u1:=array(0..N1,[]):pt1:=array(0..N1,[]):

for i from 0 to N1 do t1[i]:=evalf(th*i):u1[i]:=evalf(dsolu(t1[i]));pt1[i]:=[t1[i],u1[i]]:

od:

mytab1:=eval([seq(pt1[i],i=0..N1)]):

the above code is to plot y(t) against the time t for fixed epsilon

Now the question is how to plot epsilon against the time???

I do appriciated any comments

 

 

Is it just me that is being daft, or am I correct in ascerting that there does still not exist (even in Maple 17) a command for taking the commutator of two matrices?

As far as I can tell from the help pages, there exists only a commutator of vector fields (in the tensor package), and a commutator af algebraic quantities (in the Physics package).

Not having such a command for matrices is, of course, not critical, as it is very easily programmed, but I am just surprised, for something as fundamental as checking some representation of a Lie algebra, say, requires taking such commutators.

Helloo everyone,

eq1:=((diff(f(eta),eta$3)))-a*diff(f(eta),eta$1)^2+b*f(eta)*diff(f(eta),eta$2)=0;

bc:=f(0)=0,D(f)(0)=1+c*(D@@2)(f)(0),D(f)(8)=d:

Now the question is how we can get data in the following form 

a      b     c      d         dif(f(eta),eta$2) at eta=0

1      1     1      1                  0.1

1     2      1      1                   0.2

1     2      2       1                   0.3

1     2     2      2                      0.4

2      1     1      1                  0.5

2     2      1      1                   0.6

2     2      2       1                   0.7

2     2     2      2                      0.8

In the above table, I want to vary a, b, c, d and to find out the values from the ode for dif(f(eta),eta$2) at eta=0

Here is my try but no luck

 

sol:= (a1,b1,c1,d1)->dsolve({bc,eq1}), numeric,output = array([0]);

p:=proc(a1,b1,c1,d1)
subs(sol(a1,b1,c1,d1):-value()(a1,b1,c1,d1),Vector[row]([a1,b,c,d,rhs(sol[3])])) #dif(f(eta),eta$2) at eta=0 is called as rhs(sol[3])
end proc;

ha:=.01: hb:=.1: hc:=0.1: hd:=0.1: #Increments in a, b, c and d, respectively
Ia:=2: Ib:=2: Ic:=2: Id:=2: #Number of increments
A:=Matrix(ha*hb*hc*hd,5); #Rows: [a,b,c,d,dif(f(eta),eta$2) at eta=0]

r:=0:

for i from 1 to Ia do
q:=sol(i*ha);
for j from 1 to Ib do
v:=q:-value(b=j*hb);

for l from 1 to Ic do

w:=v:-value(c=j*hc);
for k from 1 to Id do
r:=r+1;
A[r,..]:=subs(v(hd*k),subs(w(hc*l),Vector[row]([i*ha,b,c,d,rhs(sol[8])])))
end do

end do

end do
end do;
time()-t0;

interface(rtablesize=infinity);

 

A;

 

Thanks

Hello, I have a term that do not have the variable 'n' in it, but why is the calculated number different? For example, why is

QQ:=Matrix([[3],[4],[1]]);

for m from 1 to 2 do
for n from 1 to 2 do
QQ:=(QQ*m)+QQ;
end do:
end do:

Answer: QQ:=Matrix([[108],[144],[36]])

 

different from

 

QQ:=Matrix([[3],[4],[1]]);

for m from 1 to 2 do
QQ:=(QQ*m)+QQ;
end do:

Answer: QQ:=Matrix([[18],[24],[6]])

Hi MaplePrimers,

I'm trying to solve a system of algebraic equations using 'solve' [float].  I'd prefer to use 'solve' over 'fsolve', as 'solve' solves my system in about 0.05s, whereas fsolve takes about 5 seconds.  I need to solve the system repeatedly at a different points, so time is important.  I don't know why there is such a large difference in time ... 

I have a few piecewise functions of order 3 to 5.  It solves fine with the other (piecewise) equations, but adding one piecewise function which gives me an error while trying to solve:

Error, (in RootOf) _Z occurs but is not the dependent variable.

I think this is due to solve finding multiple solutions.  Is there a way to limit solve to only real solutions?

Thanks in advance!

First 1484 1485 1486 1487 1488 1489 1490 Last Page 1486 of 2426