Maple 2017 Questions and Posts

These are Posts and Questions associated with the product, Maple 2017

Hi Maple Expert,

c*(r-1)*exp(x*beta)/((1+varphi*exp(x*beta))*(-varphi*exp(x*beta)*r+varphi*exp(x*beta)+1))

c = exp(exp(x*beta)*(r-1)/(1+varphi*exp(x*beta)))

with

ln(r) = varphi*exp(x*beta)*(r-1)/(1+varphi*exp(x*beta))-1

Please help me, and thank you in advance.

 

Regards,

Sarni

 

Maple gives me the incorrect answer to the hundredth place. (arithmetic.mw)

>15000*(1+.06/365)^(10*365)
>                        27330.47804

I tried using an exact fraction 15000*(1+(6/100)/365)^(10*365) as well.

i) D(X,Y) , D(X,Z) ,D(Y,Z) COVARİANT DERİVATİVE ?

İİ) [X,Y] LİE OPERATOR ? 

İİİ) R(X,Y)Z = D DZ - DDZ - D[X,Y] Z

This may be a stupid question, but I am having elementary trouble with pdsolve.

I have the following pde system:

PDE:=[diff(f(x,xp),x)=-(1/2)*(L*xp+2*x)*kl,diff(f(x,xp),xp)=-(1/4)*kl*L*(L*xp+2*x)];

Trying to solve it:

pdsolve(PDE)                                                          

I get this error message:

Error, (in pdsolve/sys) too many arguments; some or all of the following are wrong: [{f(x, xp)}, handlenonrationalfunctionsofdependentvariables = false]


I don't understand any of this; can someone enlighten me?

TIA

M.D.

pde.mw

 

Is there any Maple code that allows to view a complex function using the "domain coloring" technique?

This technique is described for example in Wikypedia: https://en.wikipedia.org/wiki/Domain_coloring

how to compute example 1 of linear schrodinger equation?

[Edit: uploaded .pdf file of M.M. Mousa and S.F. Ragab, Z. Naturforsch. 63a, 140 – 144 (2008) removed for copyright reasons]

Dear Users,

I am solving a large system of linear equation with the Hybrid solver. Up to 2400 equations, I get a solution, but if I change the number of equations to 3000, I don't get any solution in fact solution entry reads Float(undefined). All the entries in matrix and vector are floating point decimal with 32 digits of accuracy. Any idea how to overcome this?

 

thanks.

 

i attach my file

maple_pita_he.mw

Suppose I have

solution:=fsolve(f(x,y)=0,x,y)

this returns 

x=<result>, y=<result>

I want to continue the computation in my worksheet by assigning values to x and y without copying the numerical values by hand.

x:=<result>

y:=<result>

Then I want to make more computations with x and y.

It is too time consuming to copy the numbers by hand each time I run the worksheet

Larry

 

 

And y

In the following case evalhf Int not working. Please help

 

evalhf.mw

Having problems with solving PDE with symbolic BCs. 

u(x,y,t,M,A); 

 M,A,x are constants for this problem. 

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>Code Starts

pde := diff(u(x, y, t), t)-.5*(diff(u(x, y, t), y, y))-A*sin(M*x-t) = 0

bc[1] := u(x, 0, t) = 0

bc[2] := u(x, 10, t) = A*sin(M*x-t)

sys := [pde, bc[1], bc[2]]

pdsolve(sys)

>>>>>>>>>>>>>>>>Code ends

I don't get any solution after this.
Moreover, in the second BC, I would like to change 10 to inifnity. 

Thank you in advance for your help. 

Hello,

I have a matrix of size m*n and I want to apply a procedure "f" to each entry of the matrix. But I want to do this in parallel to reduce the computation time.

I used: Matrix(n, m, (i,j) -> Grid:-Seq( f (M (i,j) ) ,i=1..n, j=1..m) ); 

but I'm not satisfied with the result, I want the calculation to be faster. Are there any other methods?

Hi, how can you in maple take the derivitve of a function that consists of sum terms in it? (preferable in document mode)

For example I have this expression (from a math book):

f = N+k*(sum(ln(x__i-B), i = 1 .. N))-N*k*(sum((x__i-B)^k*ln(x__i-B), i = 1 .. N))/(sum((x__i-B)^k, i = 1 .. N))

What I then want to do is to derive this function with respect to k.
However just writing the expression like above it seems like mable doesn't keep the summation terms but evaluates them in a sense. So not sure how to set it up correctly in order to make the derivitive.

Taking the derivitive of f with respect to k, the solution should give something like this:

 

 

I'm trying to plot a function involving exp but keep getting warnings.

How can i avoid this?

plot(2*cos(t)/sqrt((1+exp(-eps*t))*(4/a^2-1)))

but getting the warning message

"Warning, unable to evaluate the function to numeric values in the region; complex values were detected"

Hello

I have a series of plots saved in fig0 (fig0:=rtable(1..number_of_figures);).  I had them plotted using plot:-display(fig0) but I could not figure out how to remove the frame box that separates each figure nor how to control the space between them when using size.

 

An exaggerated example follows

Many thanks

Ed

 

 

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