MaplePrimes Questions

Since (1/h)[f(i+1,t)-f(i,t)]=f(x,t)_{x} as h goes to zero, 'i' is the discrete index along x-axis. How to do it in Maple? How to reduce Eq. (5) into continuous derivatives?

restart

with(LinearAlgebra)

with(PDEtools)

with(Physics)

with(plots)

Setup(mathematicalnotation = true)

[mathematicalnotation = true]

(1)

``

U := proc (i, t) options operator, arrow; Matrix([[1+I*(q(i+1, t)-q(i, t))/lambda, I*(r(i+1, t)-r(i, t))/lambda], [I*(r(i+1, t)-r(i, t))/lambda, 1-I*(q(i+1, t)-q(i, t))/lambda]]) end proc

proc (i, t) options operator, arrow; Matrix([[1+Physics:-`*`(Physics:-`*`(I, q(i+1, t)-q(i, t)), Physics:-`^`(lambda, -1)), Physics:-`*`(Physics:-`*`(I, r(i+1, t)-r(i, t)), Physics:-`^`(lambda, -1))], [Physics:-`*`(Physics:-`*`(I, r(i+1, t)-r(i, t)), Physics:-`^`(lambda, -1)), 1-Physics:-`*`(Physics:-`*`(I, q(i+1, t)-q(i, t)), Physics:-`^`(lambda, -1))]]) end proc

(2)

``

V := proc (i, t) options operator, arrow; Matrix([[-((1/2)*I)*lambda, -r(i, t)], [r(i, t), ((1/2)*I)*lambda]]) end proc

proc (i, t) options operator, arrow; Matrix([[Physics:-`*`(Physics:-`*`(Physics:-`*`(Physics:-`*`(1, Physics:-`^`(2, -1)), I), lambda), -1), Physics:-`*`(r(i, t), -1)], [r(i, t), Physics:-`*`(Physics:-`*`(Physics:-`*`(1, Physics:-`^`(2, -1)), I), lambda)]]) end proc

(3)

NULL

z := diff(U(i, t), t)+U(i, t).V(i, t)-V(i+1, t).U(i, t)

Matrix(%id = 4525182530)

(4)

z11 := simplify(lambda*z[1, 1]/h, size) = 0

I*(r(i+1, t)^2-r(i, t)^2+(D[2](q))(i+1, t)-(diff(q(i, t), t)))/h = 0

(5)

NULL

Download limit.mw

Hi:

I am using solve(...,allsolutions)

and Maple is giving me the default "_Z1~" as part of the solution. No problem.

But when I go back and run the same statement again without a restart, it gives me "_Z2~" and my program fails because it is looking to substitute a value for "_Z1".

How do I reset the naming convention without restarting so I can get the same output each time I run the same statement. (BTW: The same thing happens with Veil where it increments the indices of the Veil symbol each time you run the same statement)..

Thank you.

When opening a new Worksheet I am given an option to start a new server. When I close said worksheet the server closes. With no worksheets open I can see "Server 2" is available. If use it to open a new worksheet and the close said worksheet, "Server 2" remains available. Is this normal? Is it actually available or is it just a display feature?

I am really confused by this behavior. Should the solution be different when calling dsolve(ode) vs. dsolve(ode,[x(t),y(t)]) where here ode is list of two coupled first order ode's?

Maple shows the solutions in reverse order in one case vs. the other. I do not see why adding [x(t),y(t)] should make x(t) solution now y(t)'s and y(t) solution now x(t)'s.  Here is an example

Here is worksheet. I just find the out changing very confusing. Should not the same solution for x(t) and y(t) remain the same regardless of adding the second option as list of not? What is the logic behaind this change or order, and how it one to know which is the correct one as they look different.

``

interface(version);

`Standard Worksheet Interface, Maple 2023.2, Windows 10, October 25 2023 Build ID 1753458`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1592 and is the same as the version installed in this computer, created 2023, November 27, 3:41 hours Pacific Time.`

restart;

20440

ode :=[diff(x(t), t) = (3*x(t))/2 + 2*y(t), diff(y(t), t) = x(t)/2 + y(t)]

[diff(x(t), t) = (3/2)*x(t)+2*y(t), diff(y(t), t) = (1/2)*x(t)+y(t)]

simplify(dsolve(ode,[x(t),y(t)]));

{x(t) = -(1/2)*c__2*(17^(1/2)-1)*exp(-(1/4)*(-5+17^(1/2))*t)+(1/2)*c__1*exp((1/4)*(5+17^(1/2))*t)*(17^(1/2)+1), y(t) = c__1*exp((1/4)*(5+17^(1/2))*t)+c__2*exp(-(1/4)*(-5+17^(1/2))*t)}

simplify(dsolve(ode));

{x(t) = c__1*exp((1/4)*(5+17^(1/2))*t)+c__2*exp(-(1/4)*(-5+17^(1/2))*t), y(t) = -(1/8)*c__2*(17^(1/2)+1)*exp(-(1/4)*(-5+17^(1/2))*t)+(1/8)*c__1*exp((1/4)*(5+17^(1/2))*t)*(17^(1/2)-1)}

#when using SET instead of LIST, then same solutions come out as above
simplify(dsolve(ode,{x(t),y(t)}));

{x(t) = c__1*exp((1/4)*(5+17^(1/2))*t)+c__2*exp(-(1/4)*(-5+17^(1/2))*t), y(t) = -(1/8)*c__2*(17^(1/2)+1)*exp(-(1/4)*(-5+17^(1/2))*t)+(1/8)*c__1*exp((1/4)*(5+17^(1/2))*t)*(17^(1/2)-1)}

 

Download why_solution_changes_nov_27_2023.mw

Is it possi le to ge a transfer function from a bode plot ?

How to plot this equation

 y(x):=

where,

A := Matrix([[1, -1, 1, -1], [1, 1, -1, -1], [-1, 1, 1, -1], [1, 1, 1, 1]]);
B := Matrix([[1], [0], [1], [0]])

I want to creat an interactive document for students. When user clicks in a coordinate-system a point shall come up. For this I need the relative (or absolute) coordinates of the actual mouse position. I cannot find the command for this. In other languages it is like getmousex, getmousey. Can anyone help, please?

As a part of my learning curve, I am trying to play with extending Maple's BernsteinBasis, which has only a limited support right now (BernsteinBasis - Maple Help (maplesoft.com)).

My goal is to implement basis operation on polynomials in Bernstein basis, so that derivatives, integrals and products of polynomials in  BernsteinBasis would be again expressed in BernsteinBasis.

While it looks like it is relatively easy to extend diff procedure, by using `diff/BernsteinBasis`, I didn't find anything similar for the int. Is there something like `int/BernsteinBasis`?

The problem is that when I am trying to implement my own int procedure in a module that  would extend standard int, it seems I need to manually implement logic for (at very least) linearity, so that int(p(x) + q(x), x) would decay into int(p(x), x) + int(q(x), x ) (I probably don't need more complex rewriting rules). So before trying this approach, is there any easy way such as with diff?
 

restart;

read("C:\\Users\\Igor\\Maple\\BernsteinPolynomials.mpl");

_m2141342686560

(1)

# General formula
diff(BernsteinBasis(k, n, a, b, x), x);

n*BernsteinBasis(k-1, n-1, a, b, x)/(b-a)-n*BernsteinBasis(k, n-1, a, b, x)/(b-a)

(2)

# In expressions
diff(2*x*BernsteinBasis(1, 2, 0, 1, x) + BernsteinBasis(2, 2, 0, 1, x), x);

2*BernsteinBasis(1, 2, 0, 1, x)+2*x*(2*BernsteinBasis(0, 1, 0, 1, x)-2*BernsteinBasis(1, 1, 0, 1, x))+2*BernsteinBasis(1, 1, 0, 1, x)

(3)

# Convertion to MatrixPolynomialObject works
p := diff(BernsteinBasis(1, 2, 0, 1, x) + BernsteinBasis(2, 2, 0, 1, x), x);
P := convert(p, MatrixPolynomialObject, x);
P:-Value(a);

p := 2*BernsteinBasis(0, 1, 0, 1, x)

 

P := Record(Value = Default[value], Variable = x, Degree = 1, Coefficient = coe, Dimension = [1, 1], Basis = BernsteinBasis, BasisParameters = [1, 0, 1], IsMonic = mon, OutputOptions = [shape = [], storage = rectangular, order = Fortran_order, fill = 0, attributes = []])

 

Matrix(%id = 36893490288797933188)

(4)

# Now, integrataion
with(BernsteinPolynomials);

[int]

(5)

# Still works
int(x^2, x);

(1/3)*x^3

(6)

# Not implemented but will be added later...
int(BernsteinBasis(1, 2, 0, 1, x), x);

"Will be implemented here..."

 

int(BernsteinBasis(1, 2, 0, 1, x), x)

(7)

# This is the problem: how to implement basis properties such as linearity?
int(2 * BernsteinBasis(1, 2, 0, 1, x), x);

int(2*BernsteinBasis(1, 2, 0, 1, x), x)

(8)

 

 

BernsteinPolynomials := module()
    description "Basic operations in Bernstein basis";
	option package;
	global BernsteinBasis, `diff/BernsteinBasis`;
	export int;

	BernsteinBasis := proc(k, n, a, b, x)
		description "Bernstein basis polynomial";
		if k::numeric then
			if k < 0 then 
				return 0;
			end if
		end if;
		if n::numeric then
			if n < 0 then 
				return 0; 
			end if;
			if k::numeric then
				if k > n then
					return 0;
				end if;
			end if;
		end if;
		'procname'(_passed)
	end proc;

	`diff/BernsteinBasis` := proc()
		description "Derivative of the Bernstein basis polynomial in the Bernstein basis";
		if _npassed = 6 then
			if _passed[-1] = _passed[-2] then
				_passed[2] * BernsteinBasis(_passed[1] - 1, _passed[2] - 1, _passed[3], _passed[4], _passed[5]) / (_passed[4] - _passed[3]) -
				_passed[2] * BernsteinBasis(_passed[1], _passed[2] - 1, _passed[3], _passed[4], _passed[5]) / (_passed[4] - _passed[3]);
			end if;
		end if;
	end proc;
	
	int := proc()
		description "Integral of the Bernstein basis polynomial in the Bernstein basis";
		if type(_passed[1], 'specfunc'(anything, BernsteinBasis)) then
		    print("Will be implemented here...");
		end if;
		:-int(_passed)
	end proc;

end module;

Download bernstein.mw

In my code, without knowing what the expression is, other than it has RootOf, the code called allvalues and got internal error 

Error, (in SolveTools:-Basis) invalid input: igcd received 5/7, which is not valid for its 2nd argument

Is this to be expected depending on the input, or is this some internal problem I need to report?

restart;
expr:=RootOf(R^4*b+R^2*a*_Z+2*_Z^2-exp(RootOf(tanh(1/2*(a^2-8*b)^(1/2)*(4*S-_Z)/a)^2*R^4*a^2-8*tanh(1/2*(a^2-8*b)^(1/2)*(4*S-_Z)/a)^2*R^4*b-R^4*a^2+8*R^4*b-8*exp(_Z))))

allvalues(expr)

Error, (in SolveTools:-Basis) invalid input: igcd received 5/7, which is not valid for its 2nd argument

Maple 2023.2 on windows 10

ps.  Reported to Maplesoft

To label axes, names with Maple typesetting tags can be used. This is convenient because the typesetting package does not have to be loaded and code is shorter. However, when used together with plot white spaces (mo(“ “)) sometimes do render. Below is an example where a white space after the character N is not rendered.

with(Typesetting):

ta:=Typesetting:-Typeset(`#mrow(mo("N "),mo("* "),msup(mo("mm"),mo("-2")))`)

Typesetting:-mrow(Typesetting:-mo("N "), Typesetting:-mo("* "), Typesetting:-msup(Typesetting:-mo("mm"), Typesetting:-mo("-2")), Typesetting:-msemantics = "atomic")

(1)

tb:=`#mrow(mo("N ",color="red"),mo("* "),msup(mo("mm"),mo("-2")))`

`#mrow(mo("N ",color="red"),mo("* "),msup(mo("mm"),mo("-2")))`

(2)

tc:=Typesetting:-Typeset(mrow(mo("N "),mo("* "),msup(mo("mm"),mo("-2"))))

Typesetting:-mrow(Typesetting:-mo("N "), Typesetting:-mo("* "), Typesetting:-msup(Typesetting:-mo("mm"), Typesetting:-mo("-2")))

(3)

plot(x,x=1..10,labels=[ta,tb],title=tc)

 

NULL

A workarround is adding an addtional tag mspace() or an invisible html character. Are there any others?

Since typesetting of normal Maple output shows the whitespace I am wondering if this way of plotting axis labels is intended. 

Download Typesetting_white_space.mw

Hello, I would like to integrate a Maple sheet into a LaTeX sheet. How to do ? Thanks in advance.

If one writes:

y := x+1

x+1

(1)

 

Then, one can display y = x+1 using this notation

 

'y' = y

y = x+1

(2)

 

However, regardless of the type of punctuation I use with the Explore procedure (or even the IntertForm package), the value for y is calculated. (See examples below.)  My question is:

 

How can I get Explore to write it out as in line (2) with x evaluated?

 

Examples:

(The first is a jpg of what is shown since MaplePrimes cannot show the Explore output.)

 

 

Explore('y' = y, x = 0 .. 5, echoexpression = false)

Explore(y = y, x = 0 .. 5, echoexpression = false)

Explore(InertForm:-Display(y) = y, x = 0 .. 5, echoexpression = false)

Download Explore_with_Inert_Form_of_display.mw

I am relatively new to Maple and I'm just getting used to working with units.  Please explain to me why the final calculation does not eliminate m^3 in both the numerator and denominator. Thanks for your help!

 

Problem

 

What would be the mass of a Dyson Shell set at Venus' orbit from the sun?

 

The shell is 150 ft thick and each 1m^2 section is 200 kg.

 

The entire Earth's mass is 5.97×10^24 kg

 

The entire mass of the solar system minus the sun is 2.6667×10^27 kg

``NULLNULL

Assumptions

 

Gravitational pull from the sun is uniform through the depth of the shell.

 

Venus' average orbital distance from the sun is 67,237,910 miles we will use that as.

Pi

Pi

(1)

"(->)"

3.1415926535897932385

(2)

 
Dyson[Inside] := 355016117130*Unit('ft')``

NULLDyson[Outside] := 355016117280*Unit('ft')

355016117280*Units:-Unit(ft)

(3)

NULLNULL``

Vol[Dyson] := (4/3)*Pi*Dyson[Outside]^3-(4/3)*Pi*Dyson[Inside]^3 = 75621866085188578208340000*Pi*Units:-Unit(ft^3)"(->)"0.23757309894397957472e27*Units:-Unit(ft^3)

   

Total_Weight := 200*Unit('kg')*Vol[Dyson]/m^3

(6691789940422039289112993734304/15625)*Pi*Units:-Unit(kg*m^3)/m^3

(4)

"(=)"

(6691789940422039289112993734304/15625)*Pi*Units:-Unit(kg*m^3)/m^3

(5)

"(->)"

0.13454641994365413638e28*Units:-Unit(kg*m^3)/m^3

(6)

Download Q_for_Dyson_Shell_Weight.mw

restart

V := m^4*(1-(varphi/mu)^p);

m^4*(1-(varphi/mu)^p)

(1)

V1 := diff(V, varphi);

-m^4*(varphi/mu)^p*p/varphi

(2)

V2 := diff(V1, varphi);

-m^4*(varphi/mu)^p*p^2/varphi^2+m^4*(varphi/mu)^p*p/varphi^2

(3)

f := Zeta * (varphi^2);

Zeta*varphi^2

(4)

f1 := diff(f, varphi);

2*Zeta*varphi

(5)

f2 := diff(f1, varphi);

2*Zeta

(6)

R:= simplify(((V/3-f1*V1/(3*V))/((1-kappa^2*f)/(12*kappa^2)+f1/V)));

4*kappa^2*m^4*(-3*(varphi/mu)^(2*p)*m^4+(varphi/mu)^(3*p)*m^4+3*(varphi/mu)^p*m^4-m^4-2*Zeta*(varphi/mu)^p*p+2*Zeta*(varphi/mu)^(2*p)*p)/((m^4*(Zeta*kappa^2*varphi^2-1)*(varphi/mu)^p+(-Zeta*kappa^2*varphi^2+1)*m^4+24*Zeta*varphi*kappa^2)*(-1+(varphi/mu)^p))

(7)

N:=evalf(int((3*V1*kappa^2*((2*V*V1)/3 - f1^2*V1*R/(3*V) - f1*V1^2/(3*V))/(V*(-f*kappa^2 + 1)*(-R*f1 - 2*V1))),varphi=varphi__hc..varphi__end)assuming varphi__hc > 0, varphi__hc > varphi__end);

-1.*(int(-3.*(varphi/mu)^p*p*kappa^2*(-.6666666667*m^8*(1.-1.*(varphi/mu)^p)*(varphi/mu)^p*p/varphi+5.333333333*Zeta^2*varphi*m^4*(varphi/mu)^p*p*kappa^2*(-3.*(varphi/mu)^(2.*p)*m^4+(varphi/mu)^(3.*p)*m^4+3.*(varphi/mu)^p*m^4-1.*m^4-2.*Zeta*(varphi/mu)^p*p+2.*Zeta*(varphi/mu)^(2.*p)*p)/((m^4*(Zeta*kappa^2*varphi^2-1.)*(varphi/mu)^p+(-1.*Zeta*kappa^2*varphi^2+1.)*m^4+24.*Zeta*varphi*kappa^2)*(-1.+(varphi/mu)^p)*(1.-1.*(varphi/mu)^p))-.6666666667*Zeta*m^4*((varphi/mu)^p)^2*p^2/(varphi*(1.-1.*(varphi/mu)^p)))/(varphi*(1.-1.*(varphi/mu)^p)*(-1.*Zeta*kappa^2*varphi^2+1.)*(-8.*kappa^2*m^4*(-3.*(varphi/mu)^(2.*p)*m^4+(varphi/mu)^(3.*p)*m^4+3.*(varphi/mu)^p*m^4-1.*m^4-2.*Zeta*(varphi/mu)^p*p+2.*Zeta*(varphi/mu)^(2.*p)*p)*Zeta*varphi/((m^4*(Zeta*kappa^2*varphi^2-1.)*(varphi/mu)^p+(-1.*Zeta*kappa^2*varphi^2+1.)*m^4+24.*Zeta*varphi*kappa^2)*(-1.+(varphi/mu)^p))+2.*m^4*(varphi/mu)^p*p/varphi)), varphi = varphi__end .. varphi__hc))

(8)

simplify(-1.*(int(-3.*(varphi/mu)^p*p*kappa^2*(-.6666666667*m^8*(1.-1.*(varphi/mu)^p)*(varphi/mu)^p*p/varphi+5.333333333*Zeta^2*varphi*m^4*(varphi/mu)^p*p*kappa^2*(-3.*(varphi/mu)^(2.*p)*m^4+(varphi/mu)^(3.*p)*m^4+3.*(varphi/mu)^p*m^4-1.*m^4-2.*Zeta*(varphi/mu)^p*p+2.*Zeta*(varphi/mu)^(2.*p)*p)/((m^4*(Zeta*kappa^2*varphi^2-1.)*(varphi/mu)^p+(-1.*Zeta*kappa^2*varphi^2+1.)*m^4+24.*Zeta*varphi*kappa^2)*(-1.+(varphi/mu)^p)*(1.-1.*(varphi/mu)^p))-.6666666667*Zeta*m^4*((varphi/mu)^p)^2*p^2/(varphi*(1.-1.*(varphi/mu)^p)))/(varphi*(1.-1.*(varphi/mu)^p)*(-1.*Zeta*kappa^2*varphi^2+1.)*(-8.*kappa^2*m^4*(-3.*(varphi/mu)^(2.*p)*m^4+(varphi/mu)^(3.*p)*m^4+3.*(varphi/mu)^p*m^4-1.*m^4-2.*Zeta*(varphi/mu)^p*p+2.*Zeta*(varphi/mu)^(2.*p)*p)*Zeta*varphi/((m^4*(Zeta*kappa^2*varphi^2-1.)*(varphi/mu)^p+(-1.*Zeta*kappa^2*varphi^2+1.)*m^4+24.*Zeta*varphi*kappa^2)*(-1.+(varphi/mu)^p))+2.*m^4*(varphi/mu)^p*p/varphi)), varphi = varphi__end .. varphi__hc)))

Error, (in content/content) invalid arguments

 

NULL

Download ex.mw

Can anyone help me factor this thing out, so I ll get an irreductible result?

x2 := 2*u - 2/3*(a - 1)*(a + 1)*u^3 + (26/45*a^4 - 4/9*a^2 + 26/45)*u^5 + O(u^6)

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