## strange result from algsubs...

Would someone be able to explain this strange output?

restart;
sol:=int(1/(x*sin(x)),x);
algsubs(x=t,sol);


How did Maple manage to obtain this? I tried tracing but it did not help me figure it out.  If it is of any help:

int(1/sin(x),x);

It seems algsubs got confused somewhere?

Maple 2017.2, windows.

## How can I increase the window/viewport/border arou...

I want ot add an annotation to a plot using the drawing facility. Then I export the plot. My problem is that I cannot increase the viewport of the plot without also increasing the size of the plot. For example the code:

plot(20-(20*(1/10))*P, P = 0 .. 10, labels = ["Q", "P"], scaling = constrained, tickmarks = [5, 3], size = [600, 400])

produces this plot:

I have constrained the plot and used the size option which together have the side effect of giving me more horizontal space. But this is a wretched hack! I want to size the viewport of the plot so I can write on it.

## Square root and branch cut...

For sqrt(-1), Maple returns I. Why not -I? I understand why in general Maple does not, and should not, return both signs, because sqrt is defined with a branch cut - specifically out along the negative real axis:

FunctionAdvisor(branch_cuts,sqrt(s));

But as +I and -I lie symmetrically around the branch cut, I do not understand why +I should be chosen in favor of -I. Neither the square of +I or of -I crosses the branch cut, which is,  I guess, the standard way to select a unique value, although both squares end up on the branch cut itself - the latter fact leading to the following more general consideration:

I do not understand why the square root of any negative real number (the above being just a specific case) should at all be assigned any meaning when lying as they do on the branch cut itself. I think it would be more sensible if Maple raised an error, telling you that the branch cut needs to be changed/moved if any value is to be assigned. Which leads me to the following question:

Can the branch cut of the logarithm, and thus of sqrt as well, be changed/moved? I would like it to lie out along the negative imaginary axis.

Update I: Concerning -1 lying on the branch cut itself, there is no issue, see my 'ups' in the reply to the answer by John May. But redefining the branch cut is still relevant.

Update II: Perhaps the issue raised is not all that trivial, after all. At least, it is "a subject of papers and debate", as Alejandro Jakubi formulated it in an email to me, pointing me to the article 'Function evaluation on branch cuts', by Rich and Jeffrey.

## How to fix this Error, (in Compiler:-Compile) Arra...

I was trying to answer a question by torabi 25, August 14, 2017 to speed up his calculations. I got this idea of converting the original code to a procedure - that was not easy, run the procedure and obtain a value of time() to establish a baseline, and making sure the answer from the procedure was the same as from torabi 25. So far so good. Then I would compile the procedure, execute it, and get another value for time(). Hopefully the compiled procedure will be faster than the uncompiled procedure. I am close, but - please see if you can fix my compiler error. Thanks!

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## uses of mathcontainer0 embedded component?...

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 (2)

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 (4)

 (5)

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Table 1

 (8)

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Can any one state the uses of mathcontainer?

1. It can store only one algebraic expression at a time?

2. Can it handle list of algebraic expressions?

3. Can it store list data points (x,y) for a list of curves?

4. Can there be any use for click to edit this component?

More than a simple Yes or No a simple example for each yes answer would be very helpful.

I enclose a document with list of coordinates for for three curves, expression for curve fitting, three expressions derived for these plot points (coordinates), a command for optimum y for each of the three curves (maximum y and corresponding x value),

Ramakrishnan V

## Maple 2017 Copying matrix gives _rtable...

Hey there.

And in the new version, whenever i want to copy a matrix from a result, it gives me an _rtable, and a number. The result is the same, but it makes it harder to read and i am not able to edit values in this copied matrix.

How do i change this?

## how i can reduce the runtime of the program ?...

hi..how i can rewrite section of this code as another form i,e ''for section''

I have a lot of line as this and runnig cise is time consuming.

is there another way to write this section in order to the runtime of the program is reduced??

thanks

 > restart;
 > with(LinearAlgebra):
 > with(VectorCalculus):
 > #Digits:=5: k:=6:
 > l:=0:
 > h:=1:
 > m:=4:
 > n:=4:
 > l1:=2*h:
 > l2:=2*h:
 > N:=0.5:
 > nu:=.3:
 > E_m:=70e9:
 > E_c:=380e9:
 > rho_m:=2702:
 > rho_c:=3800:
 > lambda_m:=nu*E_m/((1+nu)*(1-2*nu)):
 > lambda_c:=nu*E_c/((1+nu)*(1-2*nu)):
 > mu_m:=E_m/(2*(1+nu)):
 > mu_c:=E_c/(2*(1+nu)):
 > with(orthopoly):
 > for i from 0 to 5 do: L(i):=sqrt((2*i+1)/2)*P(i,z): end do:
 > Z:=rho_m+(rho_c-rho_m)*((1/2)+(z/h))^N;
 (1)
 > U:=lambda_m+(lambda_c-lambda_m)*((1/2)+(z/h))^N;
 (2)
 > S:=mu_m+(mu_c-mu_m)*((1/2)+(z/h))^N;
 (3)
 > d:=Matrix([[0,0,0,0,0,0,0,0],[sqrt(3),0,0,0,0,0,0,0],[0,sqrt(15),0,0,0,0,0,0],[sqrt(7),0,sqrt(35),0,0,0,0,0],[0,sqrt(27),0,sqrt(63),0,0,0,0],[sqrt(11),0,sqrt(55),0,sqrt(99),0,0,0],[0,sqrt(39),0,sqrt(91),0,sqrt(143),0,0],[sqrt(15),0,sqrt(75),0,sqrt(135),0,sqrt(195),0]]);
 (4)
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## how I can dsolve this differential equation...

hi...

how I can dsolve this differential equations. parameter p is unkown.

I want to gain w(x) and u(x) and psi(x) and p.

thanks

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 > with(PDEtools, casesplit, declare);
 (4)
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## how i can dsolve this differential equations........

hi...

how i can dsolve this differential equations and obtain w(x) and U(x) and phi(x) analytical or numerically?

thanks

 (1)

 (2)

 (3)

## How can I convert a result to a trigonometric iden...

How can I convert the result (2) to equal to the trigonometric identity (kw/s^2)*tanh(a*s/2)?

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## Books free of maple

Maple 2017

Books free. Like!!!

Lenin Araujo Castillo

## How should I save a procedure and read it into a ...

I have a module with quite a few procedures and it is getting too long and complex. Basicially I write each procedure in a seperate document, them copy and paste it into the module. I want to improve matters as save each proc and read it in to the module

e.g.  Qdim:=proc(A,B).........end proc

save Qdim , "Qdim.?"   have tried .txt ,.mla , .m  They save fine.

in the module have tried

read "Qdim.txt" etc.   I have included Qdim in export but Qdim doesnt work Qdim(A,B) returns Qdim(A,B)

which procuces an error

Error, (in unknown) could not open C:UsersRonanDocumentsMAPLERational TrinonometryQdim.m for reading

## prime notation setup changed in Maple 2017...

Not sure if this is documented explicitly to Maple users, but normally (prior to Maple 2017) interface(typesetting=extended) was all that was required to output display diff(y(x),x) as y'(x)

With Maple 2017 typesetting=extended is default and one must use with(Typesetting)  Settings(typesetprime=true) in order to output the display of diff(y(x),x) as y'(x).

Perhaps this is well documented somewhere, however I was unable to find the change.

## make latex() generate y'(x) for diff(y(x),x) ?...

I know the latex() command in Maple have many issues and I have no hope of what I will ask having a solution, but thought to ask any way.

Is there a way to make maple generate the latex for all the derivatives to use ' instead of d/dx ?

for example, given this

ode:=diff(y(x),x)=x;
latex(ode,output=string);


The Latex generated (which is correct) is

{\frac {\rm d}{{\rm d}x}}y \left( x \right) =x

but sometines I find it more readable if the latex was

y'(x)=x

which is more common in textbooks and other places. The problem also is that I am using worksheet so can't use  y'(x) as input.

But even switching to document mode, and writing it 2D math as input, the Latex output still does not match the input

So if there is a solution to this, would it require changing the latex() command itself? or can it be done at user level?

I'd like all orders of derivatives anywhere in the equation to come out as y'' etc.. so diff(y(x),x\$3) should generate the latex y'''(x) and so on.

Is there a trick to do this?

Maple 2017.2

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