## Is the symbol _i somehow special by default (ie wi...

I've been trying to figure out what i_  means in Maple. In what follows is some experimentation and then my questions.

 (1)

=

 (2)

=

 (3)

 (4)

 (5)

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 (8)

Impression:  is treated like an algebraic basis vector when the result of a function; but not in an expression.

 (9)

=

 (10)

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 (12)

Nothing really seemed to change with the Physics package being used. However, if we use the following package

 (13)

 (14)

=

=

In the middle of  =  text. Doesn't work as expected.

In the middle of  =  text.

My question is: is the symbol _i somehow special by default? Where can I find it in the documentation?

Note the second-to-last line in the Maple document pasted above: "Doesn't work as expected". The difference between this line and the next one is simply the presence of a := instead of an =. The assignment makes the vector notation differ. Is this difference a bug or some feature I am unaware of?

Here is yet another behavior that seems kinda weird to me. Given the function f defined above, D(f) gives us the expected result but D(f(x)) does not. Yet, int(f) gives an error, and we have to use int(f(x))

EDIT: a little more research indicates there is a difference between the operator and the function diff.

## What is the type `+` (obtained, for example, with ...

Reading another question today I discovered that I can use syntax like

a := 2 _i + 3 _j

b:= _i - _j

a+b

Maple computes the sum by vector component. This is very useful, and it prompted me to start reading the Multivariate Calculus Study Guide. I am still going through it but haven't seen this particular notation yet. When I check the type of above I get a result that sort of looks like `+` but actually it seems to be tilted to the right (so I guess it is italicized and represents some symbol).

What is this type?

I don't find much searching online, and I did see this page that says

"Any symbol beginning with an underscore (_) is effectively reserved for use only by library code. It is not available to users. Failure to observe this rule can lead to unexpected results."

Edit: After a bit more looking, looks like my example code is using notation available from the Physics package, which I am now reading a bit about (but it is not clear to my why this package is used since I am not importing it explicitly).

## Is it normal for Maple to be "Evaluating" for a sp...

I noticed something that seems to be new to my usage of Maple.

As I am typing in an expression in a Maple Worksheet (Document Mode), it seems Maple goes into "Evaluating" for a split second on every new keystroke.

For context, I have my own worksheet open and also the Maple Study Guide open for Multivariate Calculus. But just now I closed it and restarted Maple. A brand new worksheet has this same behavior.

Did I just miss this before or is it normal for Maple to show "Evaluating" for a split second on every keystroke (instead of just "Ready")?

## A bug in the Multivariate Calculus Study Guide...

I just wrote up a bug report (aka "Software Change Request") but got a "We are currently experiencing technical difficulties" error so the report is not being sent.

I will just post here about the bug in case anyone knows what it is.

I am going through the Multivariate Calculus Study Guide. I went to section 1.1, and was going through the examples. At the end of an example is a link "Next Example", but when I click this I get an error and have to go back to section 1.1 Table of Contents. Kind of annoying. Also, I notice that Maple simply crashes seemingly randomly when going through this study guide. Very annoying.

Here is a screenshot of the write-up to the bug report service that isn't working, for the record

I was wondering if this is something wrong with my Maple installation or if other people experience it too.

## Why does VectorCalculus:-PlotVector not work for o...

I was just trying to follow along the Multivariate Calculus Study Guide.

There is an example where we are supposed to plot a "rooted vector". Basically, a vector where the tail is not at the origin.

The commands seemed pretty straightforward but are not generating the expected results. Here is a worksheet with the commands in question

 (1)

Well wouldn't ya know? I am finally able to execute a worksheet in this question box. As you can see there is no vector being displayed. Now, after playing around with the values a bit, it seems that the root that I chose, [-2,1], seems to be the only one that won't work. In particular, the value 1 there seems to be problematic. If I use any other value (including for example 0.9999999), the vector seems to be drawn correctly.

Why doesn't it work for the original parameters I chose?

## How to draw a directed (but maybe not acyclic) gra...

For instance, given an adjacency matrix:

```convert([[1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0], [0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,
0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1,
0, 0, 0, 0, 0, 1, 0, 0], [0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0], [0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1], [0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0,
0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0,
0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0,
0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0], [0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
0], [0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
0, 0], [0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, 0, 0]], Matrix): # adjacency```

The desired diagram resembles:

The first one comes from Mathematica; the second one comes from MATLAB.
In MMA, we can use GraphLayout -> "LayeredDigraphEmbedding"; in MatLab, we can use Layout = "layered". Note that overlapping edges should be avoided in a layered plot.

Currently, since the vertices of a 2-D graph can be manually positioned, we can click, drag and place them to embed vertices, route edges, and then get a hierarchical structure as follows:

However, it's just a clumsy and fiddly job. Isn't there a fully automatic and less time-consuming method to do so in Maple?

## Brianch0n theoreme with hexagon...

Théorème de Brianchon
restart; with(plots):unprotect(gamma):
Error, missing operator or `;`
##Si un hexagone est circonscrit à un cercle, les droites qui joignent les sommets opposés passent par un même point.
_EnvHorizontalName := 'x';_EnvVerticalName := 'y';
_EnvHorizontalName := x

_EnvVerticalName := y

line := proc (x1, y1, x2, y2) options operator, arrow; (x-x1)*(y2-y1)-(y-y1)*(x2-x1) end proc:
R := 3:
ang := [0, (1/3)*Pi, 3*Pi*(1/4)+.2, 7*Pi*(1/6)+.4, 8*Pi*(1/5), 13*Pi*(1/7)]:
for i to 6 do P || i := [R*cos(ang[i]), R*sin(ang[i])] end do:
pts := [seq(P || i, i = 1 .. 6)]:
for i to 6 do tang || i := x*P || i[1]+y*P || i[2] = R^2 end do:
sol:=solve({tang1,tang3},{x,y}):Q13:=[subs(sol,x),subs(sol,y)]:
sol := solve({tang1, tang2}, {x, y}): Q1 := [subs(sol, x), subs(sol, y)]:
sol := solve({tang2, tang3}, {x, y}): Q2 := [subs(sol, x), subs(sol, y)]:
sol := solve({tang3, tang4}, {x, y}): Q3 := [subs(sol, x), subs(sol, y)]:
sol := solve({tang4, tang5}, {x, y}): Q4 := [subs(sol, x), subs(sol, y)]:
sol := solve({tang5, tang6}, {x, y}): Q5 := [subs(sol, x), subs(sol, y)]:
sol := solve({tang1, tang6}, {x, y}): Q6 := [subs(sol, x), subs(sol, y)]:
ptQ := [seq(Q || i, i = 1 .. 6)]:
line14 := line(Q1[1], Q1[2], Q4[1], Q4[2]): L14 := implicitplot(line14, x = -10 .. 10, y = -10 .. 10, color = red):
line25 := line(Q2[1], Q2[2], Q5[1], Q5[2]): L25 := implicitplot(line25, x = -10 .. 10, y = -10 .. 10, color = red):
line36 := line(Q3[1], Q3[2], Q6[1], Q6[2]): L36 := implicitplot(line36, x = -10 .. 10, y = -10 .. 10, color = red):
sol := solve({line14, line25}, {x, y}): I1 := [subs(sol, x), subs(sol, y)]:

lineP23 := line(P2[1], P2[2], P3[1], P3[2]): lineP56 := line(P5[1], P5[2], P6[1], P6[2]):
sol := solve({lineP23, lineP56}, {x, y}): gamma := [subs(sol, x), subs(sol, y)]:
Error, attempting to assign to `gamma` which is protected.  Try declaring `local gamma`; see ?protect for details.
lineP12 := line(P1[1], P1[2], P2[1], P2[2]): lineP45 := line(P4[1], P4[2], P5[1], P5[2]):
sol := solve({lineP12, lineP45}, {x, y}): beta := [subs(sol, x), subs(sol, y)]:
lineP34 := line(P3[1], P3[2], P4[1], P4[2]): lineP16 := line(P1[1], P1[2], P6[1], P6[2]):
sol := solve({lineP16, lineP34}, {x, y}): alpha := [subs(sol, x), subs(sol, y)]:
pl:= line(alpha[1], alpha[2], gamma[1], gamma[2]):
hexa := seq(implicitplot(tang||i, x = -20 .. 20, y = -20 .. 20, linestyle=3,color = blue),i=1..6);
hexa:=plot([seq([P||i,P||(i mod 6)+1],i=1..6),color=green);
hexa:=plot([seq([P||i,P||(i+1)],i=1..6)],thickness=4,color=green);
hex:=plot([[Q1,Q2],[Q2,Q3],[Q3,Q4],[Q4,Q5],[Q5,Q6],[Q6,Q1]],thickness=4,color=green);
tp := textplot({seq([op(pts[i]), cat("P", i)], i = 1 .. 6)}, 'align' = {'above', 'left'});
tpq := textplot({seq([op(ptQ[i]), cat("Q", i)], i = 1 .. 6)}, 'align' = {'above', 'left'});
TP:=textplot([[I1[],"I"],[alpha[],"alpha"],[beta[],"beta"],[gamma[],"gamma"]],'align' = {'above', 'left'});
slopes:=[seq(((dx,dy)->dy/dx)((pts[i]-pts[(i mod 6)+1])[]),i=1..6)];
lines:=zip((pt,slope)->y=slope*(x-pt[1])+pt[2],pts,slopes);
plotpts:=plot(pts,style=point,colour=red,symbol=solidcircle,symbolsize=5);
plotptQ:=plot(ptQ,style=point,colour=black,symbol=solidcircle,symbolsize=5);
plotlines:=plot(rhs~(lines),style=line,linestyle=3,colour=magenta);
cir:=implicitplot(x^2+y^2=R^2,x=-R..R,y=-R..R,color=black);
PL:=implicitplot(pl,x=-1..15,y=-15..6,color=blue,thickness=3);

hexa := implicitplot(tang1, x = -20 .. 20, y = -20 .. 20,

linestyle = 3, color = blue), implicitplot(tang2,

x = -20 .. 20, y = -20 .. 20, linestyle = 3, color = blue),

implicitplot(tang3, x = -20 .. 20, y = -20 .. 20,

linestyle = 3, color = blue), implicitplot(tang4,

x = -20 .. 20, y = -20 .. 20, linestyle = 3, color = blue),

implicitplot(tang5, x = -20 .. 20, y = -20 .. 20,

linestyle = 3, color = blue), implicitplot(tang6,

x = -20 .. 20, y = -20 .. 20, linestyle = 3, color = blue)

Error, `)` unexpected
display(plotpts,plotptQ,plotlines,hex,cir,L14,L25,L36,PL,tp,tpq,TP,axis = [gridlines = [4, color = blue]],
view=[-6..10,-15..6],scaling=constrained,axes=none,size=[800,800]);
display(plotpts, plotptQ, plotlines, hex, cir,

implicitplot(0, x = -10 .. 10, y = -10 .. 10, color = red),

implicitplot(0, x = -10 .. 10, y = -10 .. 10, color = red),

implicitplot(0, x = -10 .. 10, y = -10 .. 10, color = red), PL,

tp, tpq, TP, axis = [gridlines = [4, color = blue]],

view = [-6 .. 10, -15 .. 6], scaling = constrained,

axes = none, size = [800, 800])

NULL;
I don’t know how to correct those mistakes. Thank you to help me.

## Implicit differentiation ...

Hello everybody.

Im working on some implicit differentiation math right now. And by following the example, it is not bringing me anywhere close to the right answer.

In English it says: Given the implicit written function x^2-2*x*y+2*y^2=12. Determine the local maximum and/or minimum of y and x.

The answer (as can be seen in the maple file), is for y between 2sqrt3 and -2sqrt3, and -2sqrt6 and 2sqrt6.

The example clearly states in the solution (oplossing), that the dy/dx needs to be derived for x. But after doing that, and filling in the equation the same way the example is doing it, im not getting to the rigth answer, but -sqrt3/24, and that doesnt look like the right answer

 > #Opdracht 4
 >
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 >
 (4)
 >
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 >
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 >
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 >
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 >

Greetings,

The Function

## Indexed variable names...

This is something that has been a problem using Maple for decades.

Is it at all possible to create indexed variables ?
e.g.

R1, R2, R3 etc by defining for example R\$index and then varying \$index for 1.....n to get the required
R1,R2 .... Rn  I can assign to equations or filenames?

It will really simplify batch work.

Thanks

## How to save all user variables except for the proc...

Hello

I am experiencing some problems with procedures that are saved to a file and are read back to a new worksheet.  Grid:-Map and Grid:-Set, which work just fine when the procedures were defined in the same worksheet, complain about the input parameters.  I have tried to define the procedures again in the same worksheet, call Grid:-Set and etc but to no avail.   I would like to try to save all user variables except for the user-defined procedures and defined them again in the new worksheet, and see if that works. Is there an easy way to do that?

I am open to try whatever is suggested.

Many thanks.

Ed

## How can i find the coeffients of My parameter in t...

Hey dear friends, in the following code (which is also attached at bottom of this post)

```restart;
with(Physics[Vectors]);
Setup(mathematicalnotation = true);
with(Physics);
Setup(op = {H, I__C, I__G, Omega, R, a_, p, r, rho, v_, `&alpha;_`, `&omega;_`, `&varkappa;_`})
Newton_generalized_MatForm := m*(Omega*rho*H(t)*diff(`&varkappa;_`(t), t) - rho*diff(H(t), t)*diff(`&varkappa;_`(t), t) - rho*H(t)*diff(`&varkappa;_`(t), t, t) + diff(v_(t), t)) = f_[c] + f_[g]
```

i wish to get the  (kappa-dot) coefficients

so I used the "Coefficients" function as follows:

`Coefficients(Newton_generalized_MatForm, diff(varkappa_(t), t))`

but the results aren't as expected and it's this:

so is there a way around this , thanks in advance
Coeff.mw

Hello!
I have a document which can't be opened that contains several things I need to take my exam in a couple of days. The document has crashed and keeps telling this message: "There were problems during the loading process. Your worksheet may be incomplete". The only thing left in the document is a command and there should be several solved tasks.

I have tried to open the launch.ini file and add some script which MapleSoft suggested could sovle the problem, but I dont have access to the file by some reason. I read somewhere that danish letters such as æøå could be the reason for the document crashing. Is there any way to save the file or is it just lost? Eksamenssæt.mw

## Why Finance:-LatticePrice gives wrong price at 1 &...

I embed Maple code in Mobius for test questions. A simple 2-step CRR tree gives significantly different answer from the calculated by hand or by R's fOptions. Here is the piece of Mobius/Maple:

\$ct = maple("
with(Finance):
S0:=50; X:=50; Ty:=6./12; r:=0.07; sig:=0.3156; n:=1;
dt := Ty/n;
u  := exp(sig*sqrt(dt));
d  := 1/u;
pu := (exp(r*dt) - d)/(u - d);
pd := 1 - pu;
BT := BinomialTree(Ty,n,S0,u,pu,d,pd);
cT := ST -> max(ST - \$X,0);
Ec := EuropeanOption(cT, \$Ty):
LatticePrice(Ec,BT,\$r);
");

The answer is: 6.545478168.  Exactly the same with BlackScholesBinomialTree

The correct answer should be 6.32

In this case the solution by hand is simply e^(-0.07*05)*0.5236*\$12.50

R confirms 6.32:

CRRBinomialTreeOption(TypeFlag = "ce", S=S, X=X, Time=T, r=r, b=b, sigma=sig, n=n)@price

The error decreases with the increase of number of steps. All quantities before LatticePrice are calculated corectly. Any idea of what the reason might be?

Thanks.

## Input matrices from python into maple ...

Where to store a collection of 100 matrices of different orders in Python language.

Then I need to pass that file as input to Maple for so kind of analysis here.

If possible an example with 3 to 4 matrices in python stored in some file I don't know which will be good and how say excel or database or any other (This only mainly I am not getting any idea)

Then the maple program here takes that file as input and does calculations here in maple

Say as example Eigen values of those matrices

Here my matrices are all square matrices of various different orders

## How to draw the relation of the extension field...

This code can draw the subgroup lattice:

`DrawSubgroupLattice(GaloisGroup(x^3 - 2, x), 'indices')`

But I really want to know what the extension of field about each subgroup corresponds to, like this:

The root of the polynomial r1=21/3, r2=21/3(-1+sqrt(3) I)/2, r2=21/3(-1-sqrt(3) I)/2 in the above graph. Further, how do we draw the extension relation of this polynomial:

x5+15x+44

The maple can draw this graph? If maple can't draw it, what software can?

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