Suppose you do this

save something, afile.m;

and that later someone else does this

read afile.m;

Let's assume that this person does not know the names of the variables you have saved.
A way to get these names could be

before := { anames('user') };
read file.m:
after := anames('user') minus before minus {'before'}

I thought after would only contain something, but it also contains all the elements of before, just as if  
anames('user') minus before was not effective (see PS below)
Exemple

restart:
interface(version)
Standard Worksheet Interface, Maple 2015.2, Mac OS X, December 

   21 2015 Build ID 1097895
a:=1:
before := {anames('user')};
                              {a}
b:=2:
after := {anames('user')} minus before minus {'before'}
                         {a, b}

How can I obtain the set of the new user-asigned names?

PS: Why does displaying  before give the value assigned to a and not a itself?

before
                              {1}

Thanks in advance

The square root of x+8-square root of x+9-square root of 2x+4

I encountered a weird error while computing a set of integrals.

Here is my complete code in a .mw file
 

Download Inflow_distribution_for_forward_flight_(teetering_rotor).mwInflow_distribution_for_forward_flight_(teetering_rotor).mw

At the bottom I have an error message :"Error, Got internal error in Typesetting:-Parse : "invalid subscript selector". 

Hello,

When I try to get the magnitude of the transfer function in the uploaded file, I get this error:

Error, invalid input: `simpl/abs` expects its 1st argument, a1, to be of type algebraic, but received [0.15000e8/(-0.2137457857e-6*f^2+(2.909554620*I)*f-(0.1565896548e-13*I)*f^3+0.152600e8)]
 

How do I get the magnitude and phase of this transfer function so I can plot it as a function of frequency, f?  If you can show me how to plot it, that would help a lot as well.

Thank you,

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/temp.mw .
 

Download temp.mw

Hi experts, I need your help to find higher-order prolongation(extended infinitesimals) with the help of infinitesimals. rhelp1.mw

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/help1.mw .
 

Download help1.mw

in MAPLE. I have attached a worksheet please check it.

Kindly help me to find it

Thank you.

In general, the Graph6 format is a graph format supported by major math software, so I used it as a transitional format.

When I try to read this graph6 string with Mathematica or Sagemath, unfortunately there are unrecognized problems.  Later, I found that when copying, there would be missing the backslash . 

I'm trying to figure out this problem of copying strings.

hall*effect;
                          hall effect
Vh = B*I/qnd;
                                 I B
                            Vh = ---
                                 qnd
The Hall voltage represented as VH is given by the formula:    VH=IBqnd  Here,    I is the current flowing through the sensor    B is the magnetic Field Strength    q is the charge    n is the number of charge carriers per unit volume    d is the thickness of the sensor.;

B = 0.5*Unit('T');
q = Unit('e');
                        B = 0.5 Unit(T)
                          q = Unit(e)
n = 0.15*100000.*Unit('C')/Unit('L');
d = 10*micron;
                           15000. Unit(C)
                       n = --------------
                              Unit(L)    
                         d = 10 micron
I = 0.1*10^(-5)*Unit('A');
                      I = 0.000001 Unit(A)
Vh;
                               Vh

getting error in solution?

Please resolve

t3 :=2:R := 0.5:M:=0.5 :

EQ:={diff(F(x), x $ 4) +2*R*(   F(x)*diff(F(x), x $ 3) + G(x)*diff(F(x), x)  ) + 2*R*t3*(  2*diff(F(x), x $ 2)*diff(F(x), x $ 3) + diff(F(x), x)*diff(F(x), x $ 4) + 3*diff(G(x), x )*diff(G(x), x $ 2) )=0,
diff(G(x),x$2) - 2*R*( diff(F(x),x)*G(x)- F(x)*diff(G(x), x)  ) - 2*R*t3*(  diff(F(x),x$2)*diff(G(x),x) - F(x)*diff(G(x), x $ 2) ) =0};

IC:={ F(0)=0,  F(1)=0,   G(0)=1,  G(1)=0, D(F)(0)=0, D(F)(1)=M};
sol:= dsolve(EQ union IC,numeric,maxmesh=1024,initmesh=512,output=Array([0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1]));


Q1.mw

I have

f:=a^6*o + a^5*i + a^4*u + a^3*q + a^2*t + a

and

f1:=7*a^6*p + 6*a^5*o + 5*a^4*i + 4*a^3*u + 3*a^2*q + 2*a*t + 1

I want to divide two functions f/f1 to produce a result.

a^2*t+ a^3*(-2*t^2 + 2*q)+ a^4*(4*t^3 - 7*t*q + 3*u)(-8*t^4 + 20*t^2*q - 6*q^3 - 10*t*u + 4*i)*a^5+a^6*(16*t^5 - 52*t^3*q + 33*t*q^3 + 28*t^2*u - 13*i*t - 17*u*q + 5*o)+O(a^7)

I have tried collect and asympt, the result is not satisfactory.

Hi,

If I use a package  that I don't wnt to load, is these two is the best way to proceedcontains

• alias (P= package): 
• macro (P= package):
   

Thanks in advance

restart;
with(plots); with(LinearAlgebra);
_EnvHorizontalName := 'x';

_EnvVerticalName := 'y';

x1,y1,x2,y2,x3,y3:=0,-3,3,1,5,-2:   
A := [x1, y1]: B := [x2, y2]: C := [x3, y3]:

Barycentre := proc (A, B, t) description "Barycentre de 2 points A(1) et B(t) dans le rapport t";
return [(1-t)*A[1]+t*B[1], (1-t)*A[2]+t*B[2]] end proc;
ellip := proc (r1, r2) local a, b, c, d, e, f, D, E, F, eq1, eq2, eq3, eq4, eq5, eq6, x0, y0, EE, r3, sol, Ff, Tg;
global A, B, C;
r3 := -1/(r2*r1);
D := Barycentre(C, B, 1/(1-r1)); E := Barycentre(A, C, 1/(1-r2)); F := Barycentre(B, A, 1/(1-r3));
Ff := proc (x, y) options operator, arrow; a*x^2+2*b*x*y+c*y^2+2*d*x+2*e*y+f end proc;
Tg := proc (x0, y0, x, y) options operator, arrow; a*x*x0+b*(x*y0+y*x0)+c*y*y0+d*(x+x0)+e*(y+y0)+f end proc;
eq1 := Ff(D[1], D[2]);
eq2 := Ff(E[1], E[2]);
eq3 := Ff(F[1], F[2]);
eq4 := Tg(F[1], F[2], x1, y1);
eq5 := Tg(D[1], D[2], x2, y2);
eq6 := Tg(E[1], E[2], x3, y3);
sol := op(solve([eq1, eq2, eq3, eq4, eq5, eq6], [a, b, c, d, e]));
assign(sol);
EE := subs(f = 1, Ff(x, y) = 0) end proc;

ellip(-1, -7); tri := plot([A, B, C, A], color = blue):
 
po := plot([A, B, C], style = point, symbolsize = 15, symbol = solidcircle, color = red);
tp := textplot([[A[], "A"], [B[], "B"], [C[], "C"]], 'align' = {'above', 'left'});
x := 'x'; y := 'y';
ELL := seq(implicitplot(ellip(-7/11-(1/11)*j, -1/17-3*j*(1/17)), x = 0 .. 5, y = -3 .. 1, color = ColorTools:-Color([rand()/10^12, rand()/10^12, rand()/10^12])), j = 1 .. 17);
display([tri, ELL, po, tp], view = [-.5 .. 5.5, -4 .. 1.5], axes = none, scaling = constrained, size = [500, 500]);
Explore(implicitplot(ellip(r1, r2), x = 0 .. 5, y = -3 .. 1), parameters = [r1 = -2.18 .. -.7, r2 = -3 .. -.23]);
Can you tell me why this last instruction does't work ? Thank you.
 

Hi guys ,

I have the equation dt=(L/r)*(1 - a^3/r^3)^(-1/2) dr which want to integrate on both side and then solve in terms of r.(L and a are constants). I know the answer (r=a (cosh(3t/2*L)^2/3),but it seems maple can not produce it!

Mathematical almost compute it corectly! altough i think  tanh-1, should be cosh^-1(x/a)^3/2

I would appreciate if someone can help me

Thanks so muchproblem.mw

Why does Maple write

restart;
eq:=x-infinity=0;

as 

Hi sir, I hope everyone are good in Covid situation.

I wish to obtain the dual branch solution as given in the Article.

Please help me to obtain the dual branch solution in Maple.

The article is here. akbar2014_(1).pdf

Thank you..

Hi

How can i get y value from a x value to show in a graph plot?. Like i can with the point probe, but i would like to mark it with a line.

Something like this (this is from a solution that isn't mine):

Where i am supposed to find y values to specific time values..