Here in my code I am trying to differentiate a finite summation and the command Sum is giving me a simpler evaluation than the command sum.

But I have a problem, the command Sum doesn't work under signal processing tool. Is there away to make it work?

For some unknown reason, the code below does not work in Maple 2018.1, but works in Maple 2015 and Maple 2017 (the idea is taken from here) 

restart; 
with(plottools): with(plots):
V1,V2,V3,V4,V5,V6,V7,V8:=[0,-1,0],[0,0,0],[1,0,0],[1,-1,0],[0,-1,1],[0,0,1],[1,0,1],[1,-1,1]:  # The vertices of the cube
Faces:=[[V1,V4,V8,V5],[V5,V6,V7,V8],[V2,V3,V7,V6],[V1,V2,V3,V4],[V3,V4,V8,V7],[V1,V2,V6,V5]]: # The list of the faces
Colors:=[green, red,RGB(1, 0, 4),blue,grey,gold]: # The list of the colors
Cube[0]:=display([seq(polygon(Faces[i],color=Colors[i]),i=1..6)]):

for n from 1 to 7 do
F[n]:=t->rotate(Cube[n-1],t, [[0,n-1,0],[1,n-1,0]]):
Cube[n]:=rotate(Cube[n-1],-Pi/2, [[0,n-1,0],[1,n-1,0]]):
A[n]:=animate(display,[F[n](t)], t=0..-Pi/2,paraminfo=false);
od:

for m from 6 to 0 by -1 do
G[m]:=t->rotate(Cube[m+1],t, [[0,m,0],[1,m,0]]):
B[m]:=animate(display,[G[m](t)], t=0..Pi/2,paraminfo=false);
od:

C1:=display([seq(A[k], k=1..7)], insequence):
C2:=display([seq(B[k], k=6..0, -1)], insequence):
display([C1,C2], insequence, scaling=constrained, axes=normal);

I currently have a procedure that runs a fairly complicated formula involving non-commutative variables. The procedure is Vu(a, b, c) where a, b, and c are any integers. I have to run this formula whenever v_a^cu_b appears in my expression. I'm currently replacing each variable of this type with the procedure Vu(a, b, c). I'm wanted to automate that process if possible. One thought I had was to assign the value of Vu(a, b, c) to the variable v_a^cu_b for any value of a, b, and c from 1 to 5. Then use the eval command to replace the variables with the proper values. Is there any way to automate this process? Let me give you an example:

v₀u₀ = u₀v₀ + 2w₀

So u₀v₀u₀ = u₀(u₀v₀+2w₀) = u₀²v₀+2u₀w₀

I have a procedure to truncate algebraic equations. Found the basic answer hrere. I would like to make it handle equations and functions i.e f:=a x^2 +b y... and f(x,y):=c x y^2.... I can make it handle the first type but not the second.

Download Truncate.mw

Could anyone tell me why Maple changes the sign of some expressions? For example...

How to prevent this changes?

Thanks in advance,

Denis

I was pleased to observe that in Maple 2018 one can use dsolve to get solutions of matrix ODEs, e.g., X'(t)=A(t) X(t). The command is the obvious dsolve({diff(X(t),t)=A(t).X(t), X(0)=Xo}).

I was then surprised that Maple balked at the commands dsolve({diff(X(t),t)=A(t).X(t), X(0)=Xo},numeric) and dsolve({diff(X(t),t)=A(t).X(t), X(0)=Xo},numeric,{x(t),y(t)}).  Is there some error on my part?

How to linearize this complex dynamical system around x1(t)=0, x2(t)=0, x3(t)=0. Basically i want to keep nonlinear part up to fifth order on the right hand side and later want to drop it. How can i do it. The maplesheet Dyn_system.mw is attached.

Many thanks in advance.

How can I generate a sequence of random numbers Xi and Yi in [-1,1] ?

Why I couln't receive the value of Wn[0, 0, 1] in the following loop?

Download sual.mw

> restart;

>for n from 1 to 3 do

Wn[0 .. 1, 0 .. 1, n] := n*ArrayTools:-Alias(Matrix(2, 2, [[3, 1], [1, 3]]), [0 .. 1, 0 .. 1])

end do:
>Wn[0, 0, 1];

Wn[0, 0, 1]

Hello

I want to compute integral with Maple,but returns unevaluated for me.

int((-5*ln(x)^4*Pi^4-20*ln(x)^2*Pi^4-8*Pi^4+120*MeijerG([[0, 0], [1, 1, 1]], [[0, 0, 0, 0, 0], []], x^Pi))/(120*Pi^4*(-1+x)^2), x = 4/10 .. 6/10, numeric);

# ???

Thanks.

Hello all

I am teaching engineering and I use Maple to make handouts with solutions to assignments.

In Maple 2017 I used interface(displayprecision=4) to make maple it display all outputs with 4 significant digits.

Just to be clear:

If the actual value is 123.456789, then interface(displayprecision=4) makes it display 123.5 in Maple 2017. This is just how I want it.

If the actual value is 1.23456789, the interface(displayprecision=4) makes it diplay 1.235 in Maple 2017. Again, this is perfect, just how I (and most engineers) like it.

Now I have installed Maple 2018 and now interface(displayprecision=4) means 4 decimal points rather than significant digits.

So:

123.456789 => 123.4568 in Maple 2018

1.23456789 => 1.2346  in Maple 2018

This is NOT what I want.

Digits or, say, evalf[4] will not work as a fix, as I only want the DISPLAYED value to have 4 significant digits, I want the entire value used in calculations.

I am told (by Carl Love, thank you Carl) that displayprecision=4 means 4 decimal points in most versions of Maple, but I do need 4 significant digits.

Is there a fix in Maple 2018? Something that will make all output values display with 4 significant digits?

I am considering re-installing Maple 2017 and reverting to it, it turns out to be a huge work to format each output value.

I hope someone can help me, thank you in advance.

Regards, raskr

Hi guys,

I have some information about function f(x)=x^2+y(1-x)^3/4 where x domain is [0,1] and y is a parameter but i can not obtained this information with maple.

I know function f(x) for y>1.4266 is monotically decreasing and there is no turning points,(actually i can compute infection points of above function: y=1.4266 and x=4/5 )

I know function for 1.4266>y>1.0144 has two turning points a minimum for x<4/5 and a maximum for x>4/5 , but i dont know how y=1.0144 is calculated and what is the nature of this point !!! and how this relates to x><4/5 !

I know fucntion for y<1.0144 has to two turning points that the global maximum of function happens at x<0.97702, but also i can not compute 1.0144 and how this relates to x<0.97702 !!

1.mw

Thanks 

I am trying to evaluate some functions when u=v so function goes to 0/0

Example given below of the expansion series I need to produce first. But I can't produce it.
 

Download Convert_to_Sum.mw

Hello

I'd like Maple to return ln(abs(x)) for int(1/x,x) instead of ln(x).

I tried convert MMA code,but I failed.

realIntegrate[f_, x_Symbol] := 
 Simplify[Integrate[f, x] /. Log[expr_] :> Log[Abs[expr]], 
  x \[Element] Reals]; Unprotect[Integrate]; 
Integrate[f_, x_Symbol] /; ! TrueQ[$flag] := 
 Block[{$flag = True}, realIntegrate[f, x]]; Protect[Integrate];

My maple code works only for very simple cases.

REALINT := proc (f, x)

if typematch(int(f, x), ln(y::anything), 's') then

`assuming`([simplify(ln(abs(rhs(s[1]))))], [x in real])

else int(f, x)

end if

end proc;

REALINT(1/x, x);

#ln(abs(x))

REALINT(1/(x+1), x);

#ln(abs(x+1))

REALINT(1/x+1, x);

#x+ln(x) dosen't work.

Thanks.