MaplePrimes Questions

If f is a procedure e.g.  f := x -> x^2;  then f[a](b)  evaluates to f(b)  (= b^2).
Do you know where is this feature documented?
(I have used this in the past, but I need now a reference and I cannot find it).

 

Hello. There is a complex function U11[n]. Let's say I take its derivative and want to extract the real part. That is all right. Now let's say I want to get the derivative at a point and extract the real part. I can't. Are there any solutions?


HELP.mw

 

is the reason for Image result?


 

R+r__i*cos(`θ__j`)

R+(1.-0.750482401378084e-231*I)*r__i

(1)

``


 

Download cos

 

I would like to change the color and font type on the Maple-2019 inputs and outputs, so that these formatting would be applied every time I started a new document. I tried doing this through the Styles option on the Format menu, but I could not. Can anyone help? Thank you.

Which sorting related with famous sequence

for example 

sorting differential equation in a list

then access the list with famous sequence as index such as using https://oeis.org/

after access with sequence as index, use choose function to get combinations then most result are isomorphism differential ideals?

is there methods about this sorting in Richard Stanley Combinatiric book? which page of it?

Are there commands in Maple to find the order and degree of an ODE?  Searching help I could not find anything so far.

For an example, given 

restart;
ode:=(1+diff(y(x),x)^2)^(3/2)=diff(y(x),x$2)

I want the command to return 2 for the order of the ODE and degree is also 2 in this case.

I looked at DEtools package and googled. I am sure Maple have build in commands to do this without me having to parse the ODE myself to find out.

 

 

Folks,

I am new to maple and looking to solve for all value of a list and return alist as the result 

fI := [12.5, 16, 20, 25, 31.5, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, 6300, 8000, 10000, 12500, 16000, 20000];

x:= 23

y:= 36

Lp:= 8-10*log[10]((1+(f1/(2*x))^2.5)*(1+(y/(2.*f1))^1.7))

I am looking to solve Lp to give a result in the form: [a,b,c,d....] i.e solve for  all values of f1 and return a list.

Many Thanks

Last month I still can read file

by 

read “c://Users//hello//Documents//h.m”

but

now it return error

no read access c://Users//hello//Documents/

and 

in security I add the m file into readable 

I saw open file at c drive has many shell folders 

i just add m file

but still the same error

i unencrypted m file by window properties

still the same error

i save file into maple roaming directory under 12 folder , still the same error

i save into maple installation directory maple 12 , still the same error

I have a system of ODEs with parameters, p[i], and variables, x[i].

f := [
-p[1]*x[1]^2+x[2],
-2*p[1]^2*x[1]^3+2*p[1]*x[1]*x[2]+x[1]+1
];

associated with the innitial conditions:
[x[1](0) = p[2], x[2](0) = p[3]].

I am interested in sets of parameters where the solution x[1](t) is the same; if [p[1],p[2],p[3]] is associated with a solution x(p,t), and [ph[1],ph[2],ph[3]] is asociated with the solution x(ph,t); then x[1](p,t)=x[1](ph,t) for all t if and only if


[ph[1] = ph[1],
ph[2] = p[2],
ph[3] = -p[1]*p[2]^2+p[2]^2*ph[1]+p[3]]

i.e. ph[1] takes any real value, ph[2] takes the same values as p[2] and ph[3] takes a value determined by the original parameter vector and ph[1].


In a previous question it was demonstrated that x[2](ph,t)/x[2](p,t) rapidly converge on p[1] as t increases for a specific parameter vector that was given in the question (see graph below)

 

This raises the question does this limit generally hold?

I have struggled to do this in maple and I am suspicious of the answer i have got
i.e.
limit (x[2](ph,t)/x[2](p,t),t=infinity)=+/- infinity

My question is
+ when does a finite limit exist?
+ what is the finite limit?

 

Hello,

I would like to see if MAPLE fits our needs. In order to see that I would like to consider the example which is posted in H. Iwaniec :"Introduction to the spectral theory (...)" p. 36, that is as follows:

 

Suppose that you have a PDE as follows:

 

 

This PDE has the following point symmetries:

 

These differential operators are the representations of the following matrix algebra:

 

1. I would like to see the MAPLE commands, which give the algebra $v_1, v_2, v_3$ 

2. I would like to see those commands, which give you the algebra $v_1, v_2, v_3$ as a representation of $X_1, X_2, X_3$.

3. Given the algebra $v$ I would like to see the commands which give you the Laplace-Beltrami operator $\Delta_{LB}=y\partial_{xx} + y\partial_{yy}$

 

( P.s. sorry for the intransparent form, I do not know how to insert formulae in the comment.)

 

Thanks in advance.

G45073

 

possible to solve following equation with unknown parameter omega.

parameter constant.

I see before for one dimension ode this type equation was solved.

Now for 2d equation is possible?

can consider or I can send again.

Best

2d-2

 

Dear Maple users

I have a question about performing operations on a matrix and another one about retrieving information from a matrix. I am looking for the easiest (hopefully also the shortest) way to do it:

1. Given a matrix with several rows and columns. I want to permute the rows in such a way that the entries in a specific column are ordered (either ascending or decending as wished).

2. Given a matrix with several rows and columns. I want to count how many entries in a specific column are above a certain given fixed value.   

I am pretty sure some of you guys out there can do it in an elegant way. Examples will be appreciated.  

Regards,

Erik


 

pde1 := k*(diff(u(x, t), x, x)) = diff(u(x, t), t)

k*(diff(diff(u(x, t), x), x)) = diff(u(x, t), t)

(1)

iv1 := u(0, t) = 0, u(L, t) = 0, u(x, 0) = 2;

u(0, t) = 0, u(L, t) = 0, u(x, 0) = 2

(2)

pdsolve([pde1, iv1], u(x, t))

u(x, t) = Sum(-4*(-1+(-1)^(_Z4*csgn(1/L)))*sin(Pi*_Z4*x/L)*exp(-Pi^2*_Z4^2*k*t/L^2)/(Pi*_Z4), _Z4 = 1 .. infinity)

(3)

subs(`~`[_Z4] = n, %)

u(x, t) = Sum(-4*(-1+(-1)^(_Z4*csgn(1/L)))*sin(Pi*_Z4*x/L)*exp(-Pi^2*_Z4^2*k*t/L^2)/(Pi*_Z4), _Z4 = 1 .. infinity)

(4)

``

 
"I would like to replace the symbol _Z4~ with the letter n. I tried with the subs command, but I could not. Can anyone help"?"" ""


 

Download evaluate_a_sum.mw

Why am I not able to use my MaplePrimes login credentials to login into MapleCloud?

Hello,

I am facing a problem to calculate the variable "al" in a equation like shown below.

fe := int(sqrt(1+(-5.557990765*sin(5.557990765*x)-7.3*cos(5.557990765*x)-5.6*sinh(5.557990765*x)+7.3*cosh(5.557990765*x))^2), x = 0 .. al) = .5

Is there any method in maple to solve it even through using numeric methods.

I'm forward to your response.

Thank you very much!

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