Hi all

I dont know why some Z1 appears on the screen and the code does not converge.
please help me
thanks alooooot

restart;
n:=3;
nn:=3;
m:=1;
BB:=1;
BINF:=5:
pr:=7;
digits:=10;
>
eq1:=diff(f(tau),tau$3)+((3/5)*f(tau)*diff(f(tau),tau$2))-(1/5)*(diff(f(tau),tau$1))^2+((2/5)*tau*diff(h(tau),tau$1))-((2/5)*h(tau))-BB*diff(f(tau),tau$1)=0;
eq11:=(1/pr)*diff(h(tau),tau$3)+(3/5)*f(tau)*diff(h(tau),tau$2)=0;

h(tau):=sum(p^i*h[i](tau),i=0..nn);
f(tau):=sum(p^i*f[i](tau),i=0..n);

H1:= p*(diff(f(tau),tau$3)+((3/5)*f(tau)*diff(f(tau),tau$2))-(1/5)*(diff(f(tau),tau$1))^2+((2/5)*tau*diff(h(tau),tau$1))-((2/5)*h(tau))-BB*diff(f(tau),tau$1))+(1-p)*(diff(f(tau),tau$3)):
H11:= p*((1/pr)*diff(h(tau),tau$3)+(3/5)*f(tau)*diff(h(tau),tau$2))+(1-p)*(diff(h(tau),tau$3)):
>
eq2:=simplify(H1):
eq22:=simplify(H11):
eq3:=collect(expand(eq2),p):
eq33:=collect(expand(eq22),p):
eq4:=
convert(series(collect(expand(eq2), p), p, n+1), 'polynom');
eq44:=
convert(series(collect(expand(eq22), p), p, n+1), 'polynom');
for i to n do
s[i] := coeff(eq4, p^i) ;
print (i);
end do:
for i to nn do
ss[i] := coeff(eq44, p^i) ;
print (i);
end do:
s[0]:=diff(f[0](tau), tau$3);
ss[0]:=diff(h[0](tau), tau$3);
ics[0]:=f[0](0)=0, D(f[0])(0)=0, D(f[0])(BINF)=0;
icss[0]:=h[0](BINF)=0, D(h[0])(0)=1, D(h[0])(BINF)=0;

dsolve({s[0], ics[0]});
f[0](tau):= rhs(%);
#dsolve({ss[0], icss[0]});
h[0](tau):= -exp(-tau); #;rhs(%);

>
>
for i to n do
f[ii-1](tau):=convert(series(f[ii-1](tau), tau, nn+1), 'polynom');
h[ii-1](tau):=convert(series(h[ii-1](tau), tau, nn+1), 'polynom');
s[i]:=simplify((s[i]));
ics[i]:=f[i](0)=0, D(f[i])(0)=0, D(f[i])(BINF)=0;
dsolve({s[i], ics[i]});
f[i](tau):=rhs(%);
ss[i]:=(ss[i]);
icss[i]:=h[i](BINF)=0, D(h[i])(0)=0, D(h[i])(BINF)=0;
dsolve({ss[i], icss[i]});
h[i](tau):=rhs(%);

end do;

f(tau):=sum((f[j])(tau),j=0..n);
with(numapprox):

plot(diff(f(tau),tau),tau=0..5,color=blue,style=point,symbol=circle,symbolsize=7,labels=["tau","velocity"]);
plot(pade(diff(f(tau),tau), tau, [7, 7]),tau=0..5,color=blue,style=point,symbol=circle,symbolsize=7,labels=["tau","velocity"]);

I am using "Maple 15" and "Windows 7" and I want to share the tip for using "Classic worksheet" and "GR Tensor". Windows 7 is 64-bit but you can use Classic worksheet and GR Tensor, which work basically in 32-bit, by simply downlording "32-bit Maple 15" !! I haven't tried other more current versions of Maple but Maple 15 works well: you can choose 32-bit Maple in the download options.

Enjoy the Classic worksheet and GR Tensor. Good luck !  

I'm trying to display some flow lines for a vector field. The vector field I have is:

What I put into Maple is:

I've tried this with a number of points, but I always get an error message along the lines of:

"Error, (in Student:-VectorCalculus:-FlowLine) cannot determine if this expression is true or false: (2.*(1)(0)-4.)^2+(-2.+4.*(1)(0))^2 < 0.9e-9"

Could someone please shed some light as to what's going wrong for me? I would be very grateful for any help.

Thanks.

Hi there!

I wrote a piece of code which spits out the numerical datapoints (x,y(x)) corresponding to a function y(x). So that the result is accurate, I need quite a lot of data points - currently I am working with 5k.

In order to work with this function later, I interpolated it with a Spline. For instance, I would like to sample the function values on a fifferent grid, etc.. However the evaluation of this function really takes up hell of a lot of time, and the reason seems to be, that it, being a spline on 5k nodes, is simply a huge expression.

Is there a better way to do this? Are other fitting functions than a spline maybe better suited?

Thanks for help!

I need to get rid of the type "constant" for gamma. In Maple, gamma is defined as Euler's constant by default. While it is easy enough to unprotect(gamma) and then get rid of its value, Maple will refuse to solve an equation for gamma, as it remains of type constant even after deassigning it. So I need to regain gamma as a variable.

Some may feel this is an unwise thing to do. But it actually is not: I am writing a document involving physics, and gamma is the accepted symbol for the relativistic energy. I cannot avoid using that, lest mass confusion ensues (this involves students). I really don't want to write gammar instead. Euler's constant, otoh, does not figure at all in my document.

Note that I need a solution that works in Maple 15 and later as I am working in a heterogeneous environment as far as Maple versions are concerned.

Thanks in advance,

Mac Dude

i have got alot of mixed and high degree derivatives. For example:

u[x]*u[x,t]*eta[x,t]+u[]^2*u[x]*eta[x]+kis(x,y)u[x,t]^2*u[]+eta(x, y)*u[]*u[x]^2+ksi[x,t]*u[x]^2*u[x,t]+......

like this alot of terms

my question is how can i solve divided by the derivative of the u(x,t) partial differential equations system and so  how can i find eta(x,t,u) and ksi(x,t,u) 

I have the following expression (obtained from an earlier calculation):

I want to collect all the terms under one summation. So I define a rule:

collectf:=proc(f)
A::algebraic*f(a::algebraic)+B::algebraic*f(b::algebraic)\
 +C::algebraic*f(c::algebraic)+D::algebraic*f(d::algebraic)=f(A*a+B*b+C*c+D*d);
end proc:

and then

applyrule(collectf(Sum),%);

I get

Error, (in +) unable to identify A::algebraic

I used similar constructs before so I think the rule is constructed correctly. I should, however, mention that I use the Physics:-Vectors package and in fact the expression I start up with here reads, in 1-d Maple inputform:

Physics[Vectors][`+`](Physics[Vectors][`+`](Physics[Vectors][`+`](-y*(Sum((diff(a[n](r), r))/(exp(I*Pi*n/L))^2, n))/r, (2*I)*(Sum(a[n](r)/(exp(I*Pi*n/L))^2, n))*k0), y*(Sum(a[n](r)/(exp(I*Pi*n/L))^2, n))*k0^2), -y*(Sum((diff(a[n](r), r, r))/(exp(I*Pi*n/L))^2, n)))

Is my problem related to the use of Physics:-Vectors? If so, how can I get around that?

TIA,

Mac Dude

Hi everyone

I'd be pleased if you could give a hand with the exploration assistant.

1. I want the exploration assistant to appear on the same document I am working on, but everytime I use it (either by right-clicking or by the explore command) it automatically appears on a new document.

2. can I manipulate a piecewise function when using embedded components? i.e.: plot the function and varying the parameters using sliders.

thanks

cesar

https://drive.google.com/file/d/0B2D69u2pweEvMV92SGhtRGZONFk/edit?usp=sharing

a error and code in this attachment mw

i can pdsolve it, but numeric pdsolve it get error

I have this kind of problem. When I try to solve my command:

is there any way to avoid this? in order to get the answer directly...

Hello,
my question may be simple but I don't find the answer in any help guide.
when I define a function I cannot use a linearalgebra expression such as Trace.
Here is an example of what I would like to do:

If anyone can help me...
Thank you

Hi!

Say, I got an expression that depends on two variables, x and y. How can I tell Maple, that y is actually just a (real) constant, so y does not depend on x?

Because when I apply a differentiation with the "D" - command, it would always also write out expressions, where y is differentiated w.r.t. x.

Thanks!

Hi,

this question has been asked several times here already accoruding to the search function, but I didn't find an actual answer to it.

My Maple 15 gives outlarge numbers without scientific notation, so even 10^20 would be displayed as 1000....000  (20 zeroes). It seems like this is not the standard, so at one point I might have changed the way Maple displays the output, and cannot remember anymore how.

How can I tell Maple to display the output in scientiffic notation, and how can I set up the threshold of powers of ten, when this is done. (so that e.g. 100 still gets disaplyed as 100, and not as 1*10^2, but anything above gets displayed in scientific notation).

I know that I can right click on the output to change it's display form. But I want to change this generally, so I dont have to do this for any single numerical output I get.

I use Maple 15, running in Mac OS.

Thanks for help!

I have to plot 4 vectors in one graph. I have the following structure:

plot(Vector([12, 12.5, 13, 13.5, 14, 14.5, 15]), Vector([1.622712644, 1.265443137, 1.028604736, .8605013333, .7352916667, .6386248233, .5618945274]), style = line, symbol = asterisk, color = blue)

and 

plot(Vector([12, 12.5, 13, 13.5, 14, 14.5, 15]), Vector([5.483608580, 4.289400489, 3.496793877, 2.933480578, 2.513320599, 2.188469637, 1.930230220]), style = line, symbol = asterisk, color = blue)

Could you help me to plot these two curves in one graph.

please help me to find a solution for this issue...

I would like to thank you in advance

Best regards,

D.L.