Maple 2021 Questions and Posts

These are Posts and Questions associated with the product, Maple 2021

How do I write this in Maple?

Find points P and Q on the parabola y = 1 − x^2 so that the triangle ABC formed by the x-axis and the tangent lines at P and Q is an equilateral triangle.

Thank you!

How do I write this in maple?

Find the maximum value of l f"(x)l on the indicated interval. f(x)= sqrt1+x^2  [0,2]

Thank you!

How do I write this in maple?

The figure shows a circle with radius 1 inscribed in the parabola y = x^2 . Find the center of the circle.

Thank you!

Hello Dear Community

I was by pure coinsidence integrating a simple expression, f(x) = x (x^2 - 1)^5
The correct answer is F(x) = 1/12 (-1 + x^2)^6+ an arbitary Constant and if you expand F(x), you will get

F(x) = x^12/12 - x^10/2 + (5 x^8)/4 - (5 x^6)/3 + (5 x^4)/4 - x^2/2 + 1/12+ an arbitary Constant 

When I do the integration command in Maple2021 for f(x) = x (x^2 - 1)^5 , Maple2021 gives me the output in expanded form
F(x) = x^12/12 - x^10/2 + (5 x^8)/4 - (5 x^6)/3 + (5 x^4)/4 + x^2/2

Maple2021's output is missing the 1/12

I have uploaded my Maple-document regarding this issue to this link something_wrong.mw

Please do check this out and come back with a feedback since I find it disturbing that Maple2021 is giving an incomplete output for an integrating expression that is easy to solve in hand.

~~ Best regards

On my maple page i got also all the time typesetting info ?
Looked at the help page :NumberTheory,PrimeCounting

How to produce the graph of the prime counting function with the two approximations?

How do I write this out in maple?

Sketch the graph of y =x^2+7x+3/x^2 , locate all maximum and minimum values, intervals of increase and decrease, and inflection points.

Thank you!

How do I write this in maple?

Find the point on the parabola x + y 2 = 0 that is closest to the point (0, -3).

Thank you!

Graph the curve with equation y(y2 −1)(y − 2)= x(x −1)(x − 2)
At how many points does the curve have horizontal tangents?

Estimate the x-coordinates of these points.

Find the equations of the tangent lines at the points (0,1) and (0,2)

Find the exact x-coordinates of the points of these points.
Create even more fanciful curves by modifying the equation.

PLEASE WRITE STEP BY STEP IN MAPLE

How to get rid of the boundary

display(ellipse([0, 0], 2, 1, filled=true, color = red),size=[1000,500],axes=none);

or how to make the boundary the same color as the filled region?

 

Good day.

When I export an animated 3D (surface contour) plot to a gif format, the image is incomplete (please see attached file).

Can anyone suggest a way to reformulate the expressions so the animated plot can be exported to Powerpoint intact?

Thanks for reading!

MaplePrimes_Dec_5.mw 

How I can change this to smooth curve

I have not used Array much before. I made an array that has 3 elements, starting index is 0 and last index is 2.

I want each element in the array to be an empty list, so I can later add to it.  (since I do not know in advanced what size of list I need in each slot of the Array).

Array(0..2,[seq([],i=0..2)])

And this works in the code I am using. But the strange thing, each time I try to save the worksheet, I get Warning about saving Large calculation.

What large caclulation? The array is empty?

Even though the code is working, and I can add to each entry in the array lists OK and been using it OK, I think may be I am not doing something right.

How to correctly creat an Array from 0..N  and initialized each entry to empty list?

Maple 2021.2

When doing

item:=x;
res:=remove(has,item,x);

Maple returns, as expected

But when item is not a single symbol, say sin(x) or diff(y(x),x), then it no longer returns ()

item:=diff(y(x),x);
res:=remove(has,item,diff(y(x),x));

It does not return () but it now returns the input itself, as if it was not removed.

Why is that, and how to make it return () also on composite expression?  I tried flatten and inplace option. Otherwise, I will have to do a special test before. 

The strange thing is that it works on 

item:=2*diff(y(x),x);
res:=remove(has,item,diff(y(x),x));

Now it returns as expected. So now it did remove diff(y(x),x). But it does not remove it when it is on its own. I assume this is by design. But it is not intuitive to the user. One would expect it to work same way on removing `x` or `sin(x)` or `diff(y(x),x)`

   Is there a way to export routines from a package. The reason I ask, I was answering a question here and I needed two routines I have, that I put together a couple of years ago in a package. I used showstat copied, pasted and edited. Worked, but not great and would utterly fail with anything complicated. e.g. In the two routines pasted  below SignedArea on line 3 c[1]  is c   [1] that caused a minor problem.  

restart

NULL

"RonanRoutines:-SignedArea := proc(a::{Vector, list}, b::{Vector, list}, c::{Vector, list, null} := null)  local M, A;     1   if c = null then     2       A := 1/2*a[1]*b[2]-1/2*a[2]*b[1]         else     3       A := 1/2*(b[2]-c[2])*a[1]+1/2*(-b[1]+c[1])*a[2]+1/2*c[2]*b[1]-1/2*c               [1]*b[2]         end if;     4   return A  end proc:"

NULLNULL

"RonanRoutines:-CrossingNumber := proc(A::list, B::list, C::list, E::list)  local s1, s2, s3, s4;     1   s1 := RonanRoutines:-SignedArea(A,B,C);     2   s2 := RonanRoutines:-SignedArea(A,B,E);     3   s3 := RonanRoutines:-SignedArea(C,E,B);     4   s4 := RonanRoutines:-SignedArea(C,E,A);     5   if s1 = 0 and s2 = 0 and s3 = 0 and s4 = 0 then     6       'undefined'         elif 0 <= signum(s1) and signum(s2) <= 0 then     7       if 0 <= signum(s3) and signum(s4) <= 0 then     8           -1             end if         elif signum(s1) <= 0 and 0 <= signum(s2) then     9       if signum(s3) <= 0 and 0 <= signum(s4) then    10           1             end if         else    11       0         end if  end proc:  "

NULL

Download Export_from_Package.mw

Can Maple solve an ode by asymptotic expansions methods? series methods (power series or Frobenius series) work only on ordinary expansion point or removable singularity point. For non removable singularity (essential), Maple's dsolve with series method can't solve these. Also, if the RHS of the ode is not analytic at the expansion point, series method do not work. 

The asympt command only applies to algebraic expressions.

Does Maple have something similar to Mathematica's AsymptoticDSolveValue  ?

Here is an example. This is an ode with RHS not analytic (has no Taylor series) at x=0

ode:=diff(y(x),x)+y(x)=1/x;
dsolve(ode,y(x),'series',x=0)

No solution.  While in Mathematica

ode = y'[x] + y[x] == 1/x
AsymptoticDSolveValue[ode, y[x], {x, 0, 6}]

 

Here is another example of ode where the coefficient of y(x) is not analytic at x=0

ode:=diff(y(x),x)+sqrt(x)*y(x)=0;
dsolve(ode,y(x),'series',x=0)

No solution. In Mathematica

ode = y'[x] + Sqrt[x] y[x] == 0
AsymptoticDSolveValue[ode, y[x], {x, 0, 6}]

Does there exist a package in Maple that can do this? Will this functionality be added in Maple in the future if currently there is no support? ( I searched and could not find anything so far).

One possible workaround I found is to solve the ODE using normal methods (non-series), then apply the asympt command on the solution. But one needs to remove the constant of integration first, Here is the above example done this way

ode:=diff(y(x),x)+sqrt(x)*y(x)=0;
sol:=dsolve(ode);
Order:=8;
sol:=eval(sol,_C1=1);
asympt(eval(rhs(sol),x=1/y),y);
eval(%,y=1/x)

Mutliplying the above back by the constant _C1 gives same answer as Mathematica's.

Is the above how one is supposed to do it in Maple? It worked on the above simple example, but need to see if it will work for other examples. it will be better if this was more directly supported. i.e. if asympt will work directly on ode's (or a new command or a new option to dsolve similar to 'series' but call 'asympt').

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