## Is there a way to do this? [probably a bug]...

From an exercise in "Game Physics", we have the following piecewise position vector r. We wish to show that it is well-defined (as well as twice differentiable) at 0. The goal of the exercise is then to show that the Normal vector is not even continuous. So we try: ```p1,p2 := <t,t^3,0>, <t,0,t^3>; r := piecewise( t<0, p1, p2); limit(r,t=0,left);``` and unfortunately that limit gives RTABLE(149559852,MATRIX([[t], [t^3], [0]]),Vector[column]) as a result! The obvious thing to try next is to "push in" the piecewise into the components. But the

## CodeGeneration -- Some constants are not replaced ...

Hi, I have a small problem. I want to export code to Matlab. The code is mostly a long expression with some named constants. The constants are set to some values in Maple and in Maple only the x-variables are therefore unknown in the expression. However, in the exported code, some of the constants are not replaced by their values. Does someone have a clue what this depends on? Best regards Johan

## Creating Graph from its Adjacency Matrix

by: Maple
Suppose the adjacency matrix M is given. How we can get the graph of it from Maple? Can we draw the graph now? Thanx.

can I change the behavior of maple to not represent 1/sqrt(2) as sqrt(2)/2? I guess in a mathmatician's view this is a simplification, but not from an engineering standpoint. also, if I perform combine(sqrt(2)/(sqrt(m)*sqrt(k)),radical,symbolic) I get sqrt(2)*sqrt(1/m k) instead of the desired sqrt(2/(k*m))..is this related? I'm sure there is a nuance that I am not getting...

## graphing a moving particle on two 3-D sphjeres...

i am trying to plot a moving particle on two separate sphers of different radii. i have the code: restart: > with(plots): > with(plottools): > p1:=plot3d([3*sin(u)*cos(v),3*sin(u)*sin(v),3*cos(u)], u=0..Pi, v=0..2*Pi,color=red, > style=wireframe,axes=normal,scaling=constrained): > p2:=plot3d ([2.9*sin(u)*cos(v),2.9*sin(u)*sin(v),2.9*cos(u)], u=0..Pi, v=0..2*Pi,color=blue,axes=normal,scaling=constrained): > p3:=display(p1,[seq( pointplot( { [3*sin(u)*cos(v)(k/50)(n/50),3*sin(u)*sin(v)(k/50)(n/50),3*cos(u)(k/50)(n/50)],[2.9*sin(u)*cos(v)(k/50)(n/50), 2.9*sin(u)*sin(v)(k/50)(n/50),2.9*cos(u)(k/50)(n/50) ] } ) , (k,n)=(0..314,0..314) ) ],insequence=true):

## Using the 'do' function...

If i have a sequence of r[i+1] = 2r[i-1] + 3r[i] (where [i] represents subscript i) how do I use the 'do' function to go from the point where initially r[i-1] is, for example, 3 and r[i] is 4 to the point at which r[i-1] is first greater than 300 and find r[i+1] at this point. I hope this question makes sense! Thankyou

## Load own library at start-up...

Have spent much of the weekend reading the maple help files and googling but still haven't found a current way to do this on XP with v9.5. Tried editing the maple9.5.ini file to point to the folder, but it doesn't work and seems to behave more like a log file. I can use libname as a line in the worksheet but would prefer to do without as I use the modules a lot. Any suggestions would be welcome. Neil

## how to solve the question...

How do I plot f(x) in the following question? f:=x->sum(h(2^n*x)/(2^n),n = 0 .. 20) h(x)={ 2x , 0<><>

## the physics package

by: Maple
is there any way to do quantum field theory on maple 11 even if it means to have an add on package? answer will be helpful

## Eigenvectors of 2x2 Matrix with trig functions...

How can I evaluate the eigenvectors of a 2x2 Matrix with trig functions as entries? This is what I did: ```with(LinearAlgebra): K:=<<cos(theta)|sin(theta)>,<sin(theta)|-cos(theta)>>; Eigenvectors(K); Error, (in LinearAlgebra:-LA_Main:-Eigenvectors) expecting either Matrices of rationals, rational functions, radical functions, algebraic numbers, or algebraic functions, or Matrices of complex(numeric) values ``` I'm wondering why cos(theta) shouldn't be an algebraic function ?? Assuming theta to be real I get the same.

## Sorting listlists of integers

by: Maple
In a previous blog entry I described a novel method, proposed by Robert Israel, for sorting a list of lists of small positive integers, specifically those less than 256. It is significantly faster than the usual method. Roman Pearce responded with a method for rapidly sorting listlists of integers (a listlist is a list of sublists with identical number of elements), regardless of size. While not as fast as Robert's technique, it, too, is significantly faster than the usual method and has no restriction on integer size.

## Vector plot...

How can I plot some velocity vectors on a circle. the function of velocity vectors is (1+cos(t))i+(sin(t))j thank you very much