Hi there,

I have been using Maple for a while now.

I installed Maple on my Desktop PC, but I am experencing horrendous loading times, and just in general, a slow client. When I look in Task Manager I can see Java Platform SE Binary run at 0% CPU or close to 0% CPU. It uses about 600 MB of ram. I think this is the issue. On my laptop it runs much higher, and I experience no issues. My Desktop PC is significantly better than my laptop. I am running a i7-7700k with a RTX 2080, so there shouldn't be any hardware worries. 

Does anyone know what is causing this? Simple math like 1+1 takes time to execute. It is very slow.

Hope someone knows what to do.

Thanks,

Kritix.

Hi everybody

My question comes back to singularities within a differential equation.

Consider a Non-Linear differential equation of y(x), say Eq1.

When we solve this with dsolve ({Eq1, ICs}, type=numeric) we can extract the value of y(x) for each independent variable x.

Now if Eq.1 admits a singularity (for example at x=x0) that can not be removed the following message appears:

Error, (in unknown) cannot evaluate the solution further left (right) of x0, probably a singularity.

By left(right) Maple means that the solution cannot be evaluated for x<x0 (x>x0).

However, in some situations, the Linear form of Eq.1 behaves regularly for all of the values of x, I call the Linear equation as Eq.2.

Now my question is:

How can I make a conditional expression with proc and for commands that do the following requirements: 

1. Detect the singular point x0 by running a loop over x for the numerical solution of Eq.1 and write the value of x0 for different initial conditions , since the value of x0 depends on initial conditions.

2. Find the value of y(x=x0) by solving Eq.2 as the linear equation is no longer singular at x=x0.

I want to find out the suitable algorithm through which I can perform the above procedures.

Thank you very much and best regards.

Hadi

Hope that no one minds a beginners question.   How do I enter non-null k=0 robertson-walker tetrad in the physics package?  Not the tensor package as that has depreciated or the differential geometry package as notation is different there.

why is  the figure  so weird ? How can I get the smooth trajectories of the ode system?

Download as22a.mw

Dear Sir/Madam, I am new in maple and willing to use an old (yet tested) Maple V code. The program first evaluates two integrals numerically, which depend on the values of "d" and "s" (user-defined), and then computes the values of a cumulative distribution function. The problem is that, when running the code on Maple 2018, the evalf(Int) of the first integrand (named "ex1") results in "Float (undefined)". I would really appreciate your help. Thank you in advance.

#Maple V program

assume(x, real, y, real, c1, real, c2, real);
d := 3:
s := .9:
ex1:=(1-exp(-(d-y)*I*x))/I/x*exp(y*I*x/(1-I*x)):
ex1:=simplify(Re(evalc(ex1))):
f1:= unapply(ex1,x,y):
ex2:=(1-exp(-(d-y)*I*x))/I/x*exp(y*I*x/(1-I*x))/(1-I*x):
ex2:=simplify(Re(evalc(ex2))):
f2:=unapply(ex2,x,y):
t1:=evalf(Int(f1(x,s),x=-infinity..infinity));
t2:=evalf(Int(f2(x,s),x=-infinity..infinity));
cumulativeprob:=evalf(subs(c1=1/2,c2=1/2,1-((c1*t1+c2*t2)/(2*Pi)+c1*exp(-s)/2)));

cumulativeprob:=.2503779941

I get the same result here where I expected a difference to be acknowledged by the split command. Is there a more efficient way of handling this problem other than the substitution for another character, followed by executing the split  command, then substituting the substituted character with the original ?(here ":")




 

Download split_help.mw

How can I set Maple 2019 so that all inputs are of the color red?

I am using a Lenovo Notebook 64-bit.

Thank you, Jan Drösler

Plot the "moment curve" f(t)=(t,t^2,t^3) over the interval 1≤t≤2 and a tangent line at the point when t=1. Include both plots in the same display, with the moment curve red and the tangent line blue.
 

Plot the boundary of the rectangle with bounds 1≤x≤4 and 2≤y≤3 by parametrizing and plotting all four boundary segments in the same display

How do I simplify KdV equation in Maple by using =fxt))xx)?)

Download KdV_simplify

Is there lifting function for polynomials or algebra use?

expect input a list univariate polynomial , then output a list of polynomials of two variables.

it should be the reverse operation of projection.

Which library has this function in maple 12 or maple 2015?

I am trying to write a metric in Maple 2019, using the Physics package in Cartesian coordinates. I know that there is already a pre-installed way in which to set the coordinates to Cartesian, namely, if we have something like 

Setup(coordinates=cartesian);

or similarly, using the Coordiantes calling sequence, such that we may define something like

Coordinates(A=cartesian);Setup(coordinates=A);

yet, if I am not mistaken, this gives the coordinates in the following form: {x,y,z,t}, yet I seek to define the metric in the following, perhaps more arbitrary coordinate system, {x1,x2,x3,t}. Is there any way to setup the coordinate system to read like the set I just described, such that I can then take a norm of these three spatial coordaintes to be |x|? Any help would be greatly appreciated. 

   It would seem that the option style = planar  of DrawGraph()    is  failure when some graphs are planar.
   For example: 

treeof5:=[NonIsomorphicGraphs(5,4,output= graphs,outputform=graph,restrictto = connected )]:
DrawGraph ~ (treeof5, stylesheet=[vertexborder=false,vertexpadding=20]);

 

We know tree is planar graph obviously. But when I add the option style = planar ,  drawing of the first tree of list displays an error :
Error, (in GraphTheory:-Graph) vertex 1 cannot be its own neighbour in list of neighbours

I did not find any reason to explain. 

How do I find integer solutions to this non-linear equation:

8= 7(x^2+y^2+z^2)+2x+4y-8z.

Tried isolve and it wasn't working. (I guess too many variables?)

Also, if f(x,y,z) is the RHS, how do I write a loop that finds integer solutions to f(x,y,z)=c for |x|,|y|,|z|< N, say?

Suppose that a given population can be divided into two parts, those who have a given disease and can infect others, and those who do not have it but susceptible. Assume that y the proportion of infectious individuals then the rate of spread dy/dt is proportional to the number of contacts and can be described as

=y(-y), y(0)=y₀

Where y > 0 is a function of t,  is the initial proportion of infectious individuals.

1. Use MAPLE and sketch a direction field for your differential equation and include a sufficient number of solution curves and include the graph into your answer sheet.

(3 marks)

2. Find all the equilibrium solutions and determine whether they are asymptotically stable or unstable.

(4 marks)

3. Solve the above initial value problem and verify that the conclusions you reached in part(ii) are correct.

(5 marks)