how can plot a graph of V(r) against E0,B0 and EO*B0;

given that V(r)=V0/b(a-exp**-eta*r/1-exp**-eta*r)-V1exp^-eta*r/(1-exp^-eta*r)+V2exp^-2eta*r/(1-exp^-eta*r)^2;

E0=q*rho(electron)*velocity(vs)/mu;

B0=h/2^2*omega^2/16

The problem and the error in the attached worksheet. 

https://www.maplesoft.com/support/help/errors/view.aspx?path=Error,%20(in%20DocumentTools:-GetProperty)%20input%20is%20ambiguous

Download MAPLE_PLEASE_HELP.mw

Hi there,

I have a function defined as:

U:=-[0.25*exp(1/2*epsilon*t)*(1/v^2-1+exp(epsilon*t))^(-0.5)]*sin(4*t)

which I am trying to plot on a 2D graph of axes (t,u(t)).

In the specific case I have epsilon=1/10 and v=2

When I try plot(U), maple returns the error message:

Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct

Could anybody help me out please?

Many thanks

I'm trying to solve a system of nonlinear differential equations. As a minimal working example, Maple is able to solve this just fine:

restart:

pde_sys :={diff(A(t1),t1)*cos(B(t1)) = 0, diff(A(t1),t1)*sin(B(t1)) = 0}:
solving_vars := {A(t1), B(t1)}:

dsolve(pde_sys, solving_vars);

This returns [{A(t1) = _C1}, {B(t1) = B(t1)}], as expected.

However, when simply adding an arbitrary dependence on a second variable, no solution is generated

restart:

pde_sys :={diff(A(t1,t2),t1)*cos(B(t1,t2)) = 0, diff(A(t1,t2),t1)*sin(B(t1,t2)) = 0}:
solving_vars := {A(t1,t2), B(t1,t2)}:

dsolve(pde_sys, solving_vars);

Of course, this has a solution: [{A(t1,t2) = _F1(t2)}, {B(t1) = B(t1,t2)}].

Using printlevel to debug, it seems the behavior diverges when dsolve attempts to call type/ODEtools/F(x). The univariate case correctly determines that A(t1) is of the type F(x); then, these functions are correctly passed to PDEtools/assign and execution continues nominally.

For the multivariate case, A(t1,t2) is not recognized as type F(x), so no functions are passed to PDEtools/assign and execution is dominated by null sets.

Is there something I'm missing here? Or is there another way to approach this problem?

Thanks!

How to linearize this equation by Taylor function?

or otherwise written:

sin(phi2)*sin(psi1(t))*lk*m1*(diff(psi1(t), t, t))+sin(phi2)*(diff(psi1(t), t))^2*cos(psi1(t))*lk*m1

Some one can help me?

Hi!

If i do something like this:

my_points := [[1, 2], [2, .9]];
plot(my_points, style = point)

It works ok. But then i try to take units in place:

my_scaled_points := [[1*Unit('kg'), 2*Unit('hour')], [21*Unit('kg'), 7*Unit('hour')]];
plot(my_scaled_points, style = point, useunits = [Unit('kg'), Unit('hour')])

..i got empty graph. How it can be fixed?

Thank you!

Is it possible to construct in Maple the following sequence of ascending fifths?:

3/2, 3^2/2^3, 3^3/2^4, 3^4/2^6, 3^5/2^7, 3^6/2^9, 3^7/2^11, 3^8/2^12 and so on. The result always more than 1 and less than 2.

Hello,

I'm quite new to Maple and as practise, I want to calculate some z-Transformations via the definition (sum).

sum(z^(-k),k=0..infinity) assuming abs(z)>1; this one works fine (after I added the convergence condition abs(z)>1.

sum(exp(a*k*Ta)*z^(-k),k=0..infinity) assuming abs(exp(a*Ta)*z^(-1))>1; doesn't work. But I if I change the convergence condition to a*Ta<ln(z), it is calculated correctly. Why does the first attempt not work? What is the correct way to tell maple the convergence condition?

Hi all

I would like to display 'Hello' or 'try again' to see the condition introduced is satisfied or not. 

if f(a) <0 then print( a, f(a));
display ('  Hello);
else
display( ' Tru again')

end if;

But this code does not work.

Thanks for any help.

Dear all

I solve an optimization problem ( minimization or maximization) using lagrangeMultiplier theorem 

The objective function is f:=(x,y,z) =x*y+y*z;

The constraints are: x*y=1  and y^2+z^2=1;

Using a numerical method I get the follwing point 

x = 1.41421356249703, y = .707106781124551, z = .707106781248575

How can I confirm that this point is a minumum or maximum

Maybe I must use Hessian matrix or something else.

Which condition must be introduced to know the type ( maximum or minumum) this point.

Many thanks for your help

I have a system of equation as

Hi all

I have a system of equation:

sys := [x+y, 2*x+y^2];

How can I convert the previous system to this function using maple

F:=(x,y)->(x+y,2*x^2+y^2);

then how can I compute the gradient of F.

Many thanks.

Hi there,

I have an ode that I want to plot, I am trying to plot 2 different graphs on one graph and have tried using display but cannot seem to add a legend to it. Someone suggested adding a legend to each individual graph before combining them but I cannot find out how to add a legend to a DEplot. My code is as follows:

ode:=diff(u(t),t$2)-0.1*(1-64*u(t)^2)*diff(u(t),t$1)+16*u(t)=0

Q1:=v/4*sin(4*t)+epsilon*(1/8*(v-v^3)*t*sin(4*t)+v^3/128*(cos(4*t)-cos(12*t)))

A:=DEplot(ode,u(t),t=0..10, [[u(0)=0, D(u)(0)=v]], u=-0.5..0.5, linecolor=black, linestyle=dash, title="Numerical Solution"):

B:=plot(Q1, t=0..10, u=-0.5..0.5,color=blue, legend="Regular Perturbation Expansion"):

display([A,B],title="Comparing the regular perturbation expansion to the numerical solution")

Many thanks

I would like to convert a symbolic expression to text commands.  I recently used the expression palette to create a series summation; however, I was confused whether the sigma represented Sum vs sum.  I attempted to convert to string, but MAPLE attempts to evaluate the symbolic series prior to outputting the text commands.  Unfortunately, the evaluation of the series is computationally expensive & MAPLE will run out of memory.  I do not need MAPLE to evaluate the series.  How can it simply spell out the text commands that represent the symbolic form without resorting to evaluating the expression?

Download convert_to_text_command.mw

I need to find the intersection points of two circles (x-7)^2+(y-2)^2=100 and (x-11)^2+(y-5)^2=75 using the modified Newton secant method. 

I have already done this by using these two equations to make one in terms of x. But, i am looking for suggestions on how to make a multiple variable version of the secant method.

Given a sequence for example: 8, 32,128,512,2048 and so on. Suppose we do not know it is 2^(2n +1). How to make Maple to find the principle?