Hello

I wonder how integrate can be applied term by term to the following nonlinear differential equation

(diff(y(t), t))*(diff(y(t), t, t, t))-(diff(y(t), t))*y(t)^2-(diff(y(t), t))*(diff(y(t), t, t))-(diff(y(t), t))*A*y(t)

The expected output will be something like 

(diff(y(t), t))*(diff(y(t), t, t))-(1/3)*y(t)^3-(1/2)*A*y(t)^2-(1/2)*(diff(y(t), t))^2+C+int((diff(y(s), s, s))^2, s = 0 .. t)

map(x-> integrate(x,t),(diff(y(t), t))*(diff(y(t), t, t, t))-(diff(y(t), t))*y(t)^2-(diff(y(t), t))*(diff(y(t), t, t))-(diff(y(t), t))*A*y(t))

solves most of it but not the first part. 

Many thanks

Ed

I was attempting to construct  a log question and noticed a problem with the answers that are being resolved by maple.

restart:
with(StringTools):
a := 2:
b := 10:
 c := -4:
d := 5:
rs := 4:
#notice I use the word filler below, in order to randomize later and replace "filler" with various "log[base]" or "ln".
equation1 := convert(filler(a*x+b)-filler(c*x+d) = rs, string):
equationAct := parse(SubstituteAll(equation1, filler, cat(ln))):
answer := [solve(equationAct, x)]:

#it appears maple is applying the log properties and suggesting solutions outside the real domain, for the individual log expressions.  The plot of the equation seems to confirm this.
plotA := plot(lhs(equationAct), x = -10 .. 10):
plotB := plot(rhs(equationAct), x = -10 .. 10):
plots[display](plotA, plotB);

restart:
NewtonRaphsonSYS:=proc(X,F,X0,TOL,itmax)
local Xn,H,FX,J,i,m,n,Err;
m:=LinearAlgebra[Dimension](Vector(X));
Xn:=Vector(m);
H:=Vector(m);
FX:=Vector(m);
J:=Matrix(m,m);
Xn:=X0;

for n to itmax do
    FX:=eval(F,[seq(X[i]=Xn[i],i=1..m)]);
    J:=evalf(VectorCalculus[Jacobian](F,X=convert(Xn,list)));
H:=-Inverse(J).Vector(FX);
Xn:=Xn+H;

printf("%3d %.8f",n,Xn[1]);
 
for i from 2 to m do;
 printf("%.8f",Xn[i]);

end do;
for i from 1 to m do;
 printf("%.3g",H[i]);

end do;
printf("\n");
if (LinearAlgebra[VectorNorm](H,2)<TOL) then break end if;
end do;
end proc:
F:=[xy-z^2-1,xyz+y^2-x^2-2,e^x+z-e^y-3];
X:=[x,y,z];
X0:= <1,1,1>;
TOL:=0.00000001;
itmax:=10;

      [  2             2    2             x        y    ]
      [-z  + xy - 1, -x  + y  + xyz - 2, e  + z - e  - 3]
                           [x, y, z]
                Vector[column](%id = 4442374402)
                                 -8
                             1 10  
                               10
NewtonRaphsonSYS(X,F,X0,TOL,itmax);

Maple is not able to simplify x^3+a*x+b) -(y^3+a*y+b) )^2/(x-y)^4   into (x^2 + x*y + y^2 + a)^2/(x - y)^2 

wtf

p.s.  how do I get maple to show steps in simplifications

Hello people :) 

As the captian says, im trying to remove an old task i've made.
But i get this:

Error in Get, invalid object [_XML_reply_data_get("reference" =
"_Maplets_reference_12","parameter" =
"value",_XML_content("Task,UserTasks,Nyops",&Entity "#xc3",&Enity
"#xa6","tning"))]

And i have no idea what it is, but it won't erase my task :'D

Thanks a bunch in advance! 

Have a great weekend you all
Best regards Lucas :)

Hi

I am a student of economics writing my thesis. I have an inverse demand function defined:

p[i,j]=1-q[i,j]-αq[i,k]-β(q[h,j]+αq[h,k])

where α,β are scalars, i{1,2,}, j {1,2,3}, h/=i and k/=j.

I wanted to know how do i input this kind of function in the program and how do i calculate the function of q[i,j] (the inverse)

Thank you!

I would like to extract the x and y values from a list containing ordered pairs, [x,y], and display as a list.

For example, given 

  A:= [ [4,2], [9,1], [6,8] ] 

how can I obtain 

 X:=[4,9,6] and Y:=[2,1,8] 

using a simple command?

Thank you!

Why is lamba protected as something it traditionally isnt for this package?

Download main.mw

My learning exercise today is the Calkin-Wilf Tree, and the first worksheet I have the issue, due to needing to use a set operator and at that point of computation losing the ordering if it were to be a list (I have tried with a list, and was unsuccessful) none the less my question is, can I alter the ordering condition for Sets in a worksheet produced therein? 

I also encountered a strange result that I would appreciate an explaination for as seen below in the uploaded worksheet

Download Q1_MP_08112019.mw

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

Hello. Here is my question.

Download ORDERED.mw

Good day.

My question involves a set of prescribed points in the Cartesian plane. The x and y ranges are fixed. The points are connected by (imaginary) horizontal and vertical lines to produce a fixed number of blocks / grids.

An example is given in the attached file.  Grid_Example.mw

Now, I wish to reduce the intervals between these points by a scaling factor, n, so as to generate more blocks within the plane that is constrained by the x and y-ranges.

In doing so, I need to find the (x,y)-location of these points in the plane and it would also be great if I could obtain a simple plot.  

As I have several scaling factors to investigate, I was hoping someone may be able to guide me towards a simple routine to help obtain these solutions.

Once again, thanks for taking the time to read this.

Dear Maple Users, 

First of all I would like to thank for your great support and hints on making a package for Maple. It has made possible for me to construct this package here: 

restart; 
MyMat:=module()
description "My Package";
option package; 
export RegModelPlot,RegModel;
RegModelPlot :=proc(c::algebraic,xd::list,yd::list,x::algebraic)
    uses Statistics, plots:
     display
                            (  [ plot
                                 ( Fit(c, xd, yd, x),
                                   x=min(xd)..max(xd),
                                   color=blue,gridlines,
                                   title=typeset("Regressionformula\n f(x) = ", evalf[4](Fit(c, xd, yd, x))),caption=typeset("Residuals = ", Fit(c, xd, yd, x, output = residuals) ))                    
                                 ,
                            
                                 plot
                                 ( xd, yd,
                                   style=point,
                                   symbol=solidcircle,
                                   symbolsize=10,
                                   color=red
                                 )
                               ],
                               size=[800,600]
                            );
                           
                           end proc; 

    RegModel:=proc(c::algebraic,xd::list,yd::list,x::algebraic)
            uses Statistics, plots:
return  Fit(c, xd, yd, x);
end proc; 
    end module

My question is now. How do I make it installable ? Meaning, making it so I can be accessed using with the with() argument alene? I have tried to convert it to into an MLA-file and place it in the lib folder. 
 

But if I type with(MyMat) it gives me the error: 

Error, invalid input: with expects its 1st argument, pname, to be of type {`module`, package}, but received MyMat 
 

So anyone with an idea/hint on what I need to add to make the package installable? 

Thanks in advance :)

Hi 

I was wondering someone could help me with something.

Basically I've got a function of f(x,z) that I have plotted which comes from an integration that was taken over a large number of small steps. I have been able to plot this function to determine a Potential Field as a function of x and z. (No Problems so far)

However the next step that I want to be able to do is compute a field form this potential. apologies for my lack of knowing how to input into here as I am fairly new to this. To do this I have:

Field = - Nabla * Potential 

Again no problem, I can plot a gradient field from it which is great using the gradplot command. I beleive this comes as a result of the following:

gradplot = [diff(f,x), diff(f,z)]

HOWEVER I want to be able to plot a Field Strength plot (In essence a Gradient Field Strength) where it takes the magnitude of the vectors at each point. Firstly am I correct in saying that this should be:

Magnitude Field = |F| = sqrt( Fx^2+Fz^2)      where Fx is diff(f,x) and Fz is diff(f,z)

However when I try to compute this, it takes an age to evaluate and doesn't seem to make much progress. I think this may come as a result of computing square roots of large numbers/large decimal places? I was wondering whether there is any command that anyones knows of that would calculate Gradient Field Strength/Magnitude that may solve this issue? Or even who to just compute this Square root?

Hi,

i have a problem with this code ?

CodeVectorCalculus.mw

ideas ?

Thanks