MaplePrimes Questions

Hi! This is probably simple, but
I would like to know if there's an specific algorithm to do this:

let B = {x[i], i=1..n} in such a way that:

f( B ) = Sum(a[i]*b[i], i=1..N); a_i in R; b_i in B; N>n.

so Linearcomb: f->V(R).

Linearcomb( f ) =

 (Sum(a[j],j in J))*x[1]+(Sum(a[k],k in K))*x[2] + ... +(Sum(a[z],z in Z))*x[n].

with V(R) a vector space; R the Real numbers, and B the base. Neither the "factorize", nor the "simplify" are proving useful to this. Is there something i'm missng?

Please answer the commented questions in the uploaded worksheet.

Binary_search.mw

Hi everyone 

I have a problem with an animation that I dont know how to solve. 

Let's say I have three sets of coordinates. (one static and two moving dependet on time)

1:= [x1;z1]

2:= [x2(t);z2(t)]

3:= [x3(t);z3(t)]

Now I want out of these 3 points two lines that are connected  with each other like this:

line 1:= 1 and 2

line 2:= 2 and 3

These lines should move over time in the 2d space. The only point that doesnt move is point 1. In the animation there should only be the 2 lines visible for each frame. (not a trace or something like this) 

does anyone have an idea how I solve this?

Hi

I'm trying to automate this production of doubles combinations with a set scoreline in between. The minimum is 4 players, but we could have many more players, producing many combinations. 

example: 4 players, set score 2-0 for each match

with(combinat):
DBL:=choose([Novice,Weak_Intermediate,Strong_Intermediate,Advanced], 2);
DBL[1],2,DBL[6],0;DBL[2],2,DBL[5],0;DBL[3],2,DBL[4],0

#and the reverse
DBL[6],2,DBL[1],0;DBL[5],2,DBL[2],0;DBL[4],2,DBL[3],0
 

#the output contains square brackets. How do I remove them?

Does Maple Flow support the Maple Physics[Vectors] package? If so, how are vectors entered?

I have an Array A which I wanted to convert to Matrix. Doing B:=convert(A,Matrix); displays different on the screen than if A is first converted to list, then the list is next converted to Matrix.

Also the dimension in the first case if not the same as the dimension of the matrix done using the list conversion first. I expected both to give same dimension which is 10 by 3 in this example.

Should not both be the same? Does this to convert an Array to Matrix, one first needs to convert it to list, then convert the list to Matrix?

ps. thinking more about this, I think this seems to work as designed. I just expected convert to Matrix to generate the standard 2 dimensional matrix  10 by 3 automatically from the Array, but I see now that it probably does need that extra conversion to a list first.

 


 

interface(version);

`Standard Worksheet Interface, Maple 2022.1, Windows 10, May 26 2022 Build ID 1619613`

restart;

A:=Array(1..0);
for i from 1 to 10 do
   A ,= [i, i+1, i+2]
od:
B:=convert(A,Matrix);
whattype(B);
LinearAlgebra:-Dimension(B);

A := Vector[row](0, {})

Matrix(%id = 36893490060059048044)

Matrix

1, 10

restart;
A:=Array(1..0);
for i from 1 to 10 do
   A ,= [10-i, i+1, i+2]
od:
B:=convert(A,list);
B:=convert(B,Matrix);
whattype(B);
LinearAlgebra:-Dimension(B);

A := Vector[row](0, {})

B := [[9, 2, 3], [8, 3, 4], [7, 4, 5], [6, 5, 6], [5, 6, 7], [4, 7, 8], [3, 8, 9], [2, 9, 10], [1, 10, 11], [0, 11, 12]]

Matrix(%id = 36893490060058557844)

Matrix

10, 3

 

 


 

Download oct_25_2022.mw

Hi everyone 

I solve several differential equations using dsolve. Now I want to change one initial condition a little bit: 

before: u0n := u0*ms/(ms + mn)

new: u0n := u0*ms/(ms + m(t)

When solving the new system I am getting the error message: Error, (in dsolve/numeric/process_input) unknown piecewise(0 < 16-(xn(t)^2+(zn(t)-16)^2)^(1/2), 16-(xn(t)^2+(zn(t)-16)^2)^(1/2), 0) present in ODE system is not a specified dependent variable or evaluatable procedure

I am guessing this has to do with a function in an initial condition. 

Has anyone an idea how to solve this problem?

I added the maple file for the whole overview.

Thanks in advance!

Fractional part of a negative number is always positive. But maple command frac(-7.8) gives -0.8 instead of 0.2. Why is this? Though we can find it by using 1-frac(x), maple command may be there to give fractional part for all real numbers as per definition.

Like frac(9.8)=0.8 and frac(-9.8)=0.2.

Is there a command in maple?

Thanks. Ramakrishnan V

Dear all

I have the following code, that solves a linear system 
But I get the error 

Error, (in rtable/Sum) invalid arguments

code.mw

Thank you for any help 

Good day everyone,

I am trying to rotate the plots of pde solution using transplot, but it is giving me errors. Anyone with better suggestions should help. The code is attached below. Thanks

Transplot_not_working.mw

Let the square matrix A satisfy A^2023 = 0.

a. Prove: I-A is invertible.

b. If B is invertible, is B - A invertible?

This is not a Maple problem but it has something to do with math, specifically linear algebra, and I need help. Sorry if I bothered you. If possible please help me!

Dear all:

    I am trying to use the subs command to replace 5 varibles with other specific 5 varibles.

to be simple, here is issue.

Now I and using the stupid way(manually replace eachstep by my self) which did work but with some small issue such as  simplify or subs not work for replacements

all the steps I did are contained inside here:

ModelExtrinsicParasiticExtraction_QuestionsV2.mw

thanks for your help.

best regards

The following expression

limit(log(x)/x, x = 0)

returns undefined in Maple 2022.

I am not certain about if this limit exists, but shouldn't it be -infinity?

 For famous constants like pi and e, are the values stored or are they calculated?

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