Hi, 

     I've been playing around with the Physics package, and I'm confused on evaluaing derivatives of explicit funcitons of the coordinates. This code below doesnt behave as I would think. I'm trying to define z as a function of X[mu]*X[mu], and take diff(z, X[mu]). You can see that each method d_, diff,  disagree and none are satisfactory ansers. (Maple 2015, Windows 8.1 64-bit, Intel i5 Haswell) 

# Declare coordinates for 2 dimensions, flat space

restart:
with(Physics):
Setup(mathematicalnotation = true, dimension = 2):
Coordinates(X):

# Method 1: Using Define and various differential operators
Define(z):
z :=sqrt(R^2-X[mu]*X[mu]);
d_[mu](z(X));
d_[1](z(X));
diff(z, x1);  #This one is correct
diff(z, X[mu]); # off by 2

# Method #2: Using functions
# Off by a factor of 2
z2 := mu -> sqrt(R^2-X[mu]*X[mu]);
diff(z2(mu), X[mu]); # off by 2

 PhysicsDiffBug.mw

I want to make the model which moves along the specific direction (translational), So I used the "prismatic joint" to give the direction that I want to enforce. However, "Prismatic joint" only offers the direction along the "X", "Y", and "Z" axes though I want to give other direction.

Is there any way to give the specific direction (vector) to make my model move in that way ?

Hi all,

I've been working on this problem for a while and only need to figure out why the function vector is returning zeros every time I call the procedure. The problem statement is in the file I attached to this.

If any of you could help me, I would be a happy guy.

File: 1.2.mw

Just as the title says: How do I avoid Maple Prompt to appear automatically?

When writing a code in Maple Prompt and hitting enter, a new [> is created and I can't delete it. Which is unfortunate, for most of the time I want to write some TEXT afterwards, not more code.

Sometimes it doesn't happen, but I can't find the logic in it. Any ideas? Much obliged!

For an example, see this post:

http://www.mapleprimes.com/questions/203735-Print-To-Pdf-Results-In-Blank-Space

2nd picture. I asked it as a BTW-question.

Thanks in advance

hello

i have some problem when iuse the digital libray with the delay components:

i have this error: delay variable not found in dependent variable list, [`Main.TransportDelay1.x`(T)]

it seems that the delay function in the modelica language is not well treated in MapleSim . At this level:

equation
    y = if 0 < delayTime then if delayTime <= time then x_delayed else y0 else pre(x);
    x_delayed = integer(delay(x, delayTime));
end Modelica.Electrical.Digital.Delay.TransportDelay;

Thank you for your help.

hi friends

i have a problem in maple with an error

Read'dsnumsort.map';
dsnumsort(Ns(0),[x,y,z]);
for i from 0 to 1000 do;
T:=i/25;
NsT:=Ns(T):
X[i]:=rhs(NsT[C1]); Vx[i]:=rhs(NsT[V1]);
Y[i]:=rhs(NsT[C2]); Vy[i]:=rhs(NsT[V2]);
Z[i]:=rhs(NsT[C3]); Vz[i]:=rhs(NsT[V3]);
KepVec[i]:=convert(crossprod([X[i],Y[i], Z[i]],[Vx[i],Vy[i], Vz[i]]),list);
KepAbs[i]:=norm(KepVec[i],2);
od:

pacecurve({[seq(X[i],Y[i],Z[i],i=0..1000)],[[-1/(2),0,0],[1/(2),0,0]]},labels=['x','y','z']);

but i see:

Error, invalid input: seq expects 2 arguments, but received 4

can you helpe me?

Thanks

Hi I have some problems with the inert view of the limit command.

I have upload the file. 

bug_limit.mw

Thank you.

Hello!

Please help solve this equation!

restart;

Dd:=4.9*10^(-10):
n:=4.5:
m:=3.5:
ny:=20:
B:=1.47*10^(-11):
H1:=70:
H2:=20:
H:=100:
b1:=40:
b2:=80:
delt_y:=H/ny:
A_max:=b1*H1+b2*H2+10*b1:
M:=1000:



b:=y->piecewise(`and`(y>=0,y<=H1),b1,`and`(y>H1,y<H1+H2),b2,`and`(y>=H1+H2,y<=H),b1):
y:=0: eq:=0:

for j from 1 to ny do
y:=(j-1)*delt_y+delt_y/2;

eq:=evalf(eq+b(y)*sign(y-y0)*abs((y-y0))^(1/n)*delt_y);
end do;

#eq=0, y0-?
sol1:=fsolve({eq=0},{y0});

Hi

I'm trying to use the command: DocumentTools[Retrieve](path,label), but i recieve the message "unable to retrieve label reference" no mather what i do. When i use the GUI: Insert - reference and get the value it works fine, but in that way I can't assign the value to a variable in the document.

here is an example:

The document i want to retrieve a value from:

restart;

a := 5;

#a gets the label (1)

The document i want to retrieve the value to:

restart;
with(DocumentTools);

path := FileTools:-JoinPath(["test.mw"], base = worksheetdir); = "C:\Users\Nicolai\CloudStation\Nicolai\Skole stof\Sem 7\test.mw"

Retrieve(path, "());
Retrieve(path, "(1)");
Retrieve(path, "a");

#None of the above works

Is it even possible to do such thing?

with best regards

Nicolai

with(Physics) :
t:=Intc(Dirac(k1+k2+k3)*phi(k1)*phi(k2)*phi(k3),k1,k2,k3) ;

# how to force
Fundiff(t,phi(-k));

# to find
3*Intc(Dirac(k2+k3-k)*phi(k2)*phi(k3),k2,k3) ;

hi friends

i have a problem in maple with an error

 restart:
 with(plots):with(linalg):
 r:=sqrt((xi-x)^2+y^2+z^2):
 sigma:=m/l:#linear mass density
 U:=Int(G*sigma/r,xi=-L/2..L/2);
 U:=normal(value(U));
 Us:=subs(G=1,m=1,L=1,z=1.5,U);
 plot3d(Us,x=-2..2,y=-2..2,axes=boxed,style=hidden,color=red,orientation=[-80,-130],numpoints=35^2,labels=['x','y','U']);

after this i see :

 Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct.

can you help me?

Thanks for your time

Best regards

with(plots);

polarplot(1+2*sin(theta),theta=0..2*Pi);

it makes a graph made up of polar coordinate.

i wannna solve the question in cartesian coordinate

i wouldnt come up with ideas to solve it!!

please help me

for example)

y= r*sin(theta)

1+2y/r=r

y=(r^2-r)/2

...

...

y=x^n+x^n ....

x= something , something, something

Does Maple have a variable containing the directory (path) of current working file?

Thank  you.

I would like to use Newton's Method (the multivariate one) in order to solve a system of equations. From what I understand, fsolve is essentially MAPLE's version of the multivariate Newton's Method. Is there a way to do the multivariate Newton's method any other way, other than fsolve? Also, is there a way to specify our own initial guess and tolerance for the Newton's Method and to get other details such as the number of iterations?

of the improper integral of exp((1-x)/((1-x)^2+y^2)) over the unit disk x^2+y^2 <= 1 with Maple? For purists the function is assumed to be undefined at (1,0). It is not so difficult to verify that statement  by hand. It is not easy to prove that with Maple.

My try was

f := evalc(exp(Re(1/(1-x-I*y))));

VectorCalculus:-int(f, [x, y] = Circle(`<,>`(0, 0), 1), numeric);

and

evalf(Int(f, [y = -sqrt(-x^2+1) .. sqrt(-x^2+1), x = -1 .. 1]));
.

Edit. The formula for f.                  

PS.