## MaplePrimes Questions

I am new to Maple and have some questions about the LPSolve function.

I have read the help about the function but still don't understand how it works.

I would like to use LPSolve to solve a matrix maximization problem.

Which is listed in the help as : LPSolve(c, [A, b], [bl, bu], maximize)

Can anyone give me an example of how this function is used and what math equation does it apply to?

Thank you for helping.

## Evalutate expression for different values of n...

Hi,

I have the expression 1 - mul( (365 -n)/365, n=1..2).

What I want is to run the command with values of n always starting from n=1 - but also get values for n=1..3, n=1..5, n=1..i where i < 366.

I would truly appreciate help in this - I'm sure it's simple, I just can't make it work :)

Best regards,

Troels

## convert a list of equations to pair of rectangular...

"Equate - convert a pair of rectangular objects into a list of equations" How can I do the opposite? e.g. converting [a=2, b=4, c=3] into [2,4,3]

## time-dependent random numbers?...

Hello, I want to solve a DE in x(t) where the RHS of the equation is a random number that changes with time. For example: x''(t) + 10 x(t) = f(t) where f(1)=1, f(2)= 6, f(3)= -2...etc. I tried to use ran() but it solves it for a fixed random number, while I want it to be time dependent . Is there a way I can do that? Thanks

## animating line segments...

I have a set of points and I want to display them in animation joined sequentially by line segments.  What's wrong with the following code?   Maple 11 gives the message    "Error, unable to execute seq"

traj:= [2,1], [3,2],[4,3], [6,8],[3,-2]

animate( plot,  [   [seq( traj[ k ],  k=1..J )]   ]  ,  J=[ 2,3,4,5] )

## help in making a plot.......

in maple 11, can anyone give me the right commands in making a plot coords for a set of datas..... my data is about number population of 4 species per month... the independent variable is time/month, while the dependent variables are the 4 species which are frog, spiders, snakes, and beetles..... any help will be appreciated...

## Group Theory Question...

How can I derive the root diagram of the SU(2) group by using the Pauli Matrices?

thanks,

dc

## Implement a piecewise function in a DynamicSystems...

What I have done wrong?

eq := [piecewise(p(t) < prec, p(t) = C1*exp(function), p(t) >= prec, p(t) = C1*exp(function))]

params := [C1 = .2, prec = 100]

sys := DynamicSystems[AlgEquation](eq, inputvariable = [function], outputvariable = [p(t)])

But I recieve the following error message:

Error, (in DynamicSystems:-AlgEquation) cannot match the arguments to an appropriate system

## how do i use maple to differentiate to higher orde...

Hi,

I am being given the following question:

Let f(x) = tan(sin x2)−sin(tan x2). Let n be the smallest positive integer
such that f(^(n))(0) 6= 0. Then n = __.

I am suppose to differentiate f(x) using maple to solve for n, that is to differentiate the function over and over again till I am able to get say f(^(16))=0.

However, maple gets very laggy after i tried n=10.

Is there any shortcut that could help solve this problem?

Best regards,

zn.

## Memory problems on Mac...

Hi, I have the following memory problem with maple 12 on mac (intel) which (I guess) should be known already, so hopefully someone can give me a quick solution to it: I can not rise via kernelopts(datalimit=blabla...) the soft datalimit above 500 mb. ("Error, cannot raise the datalimit above the hard limit". ) This is quite weird, since I have for sure more physical memory available than that... The suggested solution for this problem according to the maplesoft FAQ (only for PPC !?!) is to edit a file named mserver_ulimit ... unfortunately this does not seem to help !

## calculating mean and distribution data from a file...

My data file is a list, where each line is

[elm1,elm2,elm3,elm4].

I would like to read through and calculate the mean of all of the elm1's.

I would like to get a distribution of the elm1 data.  For example, in 800 lines of data, if elm1 takes on values 5,6 and 7, I want to know that there are 300 5's 400 6's and 100 7's.

stats[mean](data) needs the numbers inputted.  I even thought I could pull off the elm1's into a separate list, but stats[mean] won't take a list.

Any help is appreciated.

## Maple export graphics with loop...

Hi Everyone!

I want to export several Figures with Maple at the same time. I tried

with(plots):

for i from 1 to 5 do
interface(plotdevice=ps, plotoutput=`c:/test||i.eps`, plotoptions=`color,portrait,

noborder,width=16cm,height=12cm`);
plot(cos(i*x), x = -5..5);
interface(plotdevice=inline);

od:

but it did not work. How can I create one file per Figure?

Thanks a lot,

Bernardo

## Meaning of some variables Maple give me back when ...

If I try to solve the following differential equation with simbolic parameters:

IC := p(0) = condizIni

ode := diff(p(t), t) = (QIn-QOut-derV)/((1/Boil+1/Bwall+percair/(m*p(t)))*V)

func := rhs(dsolve({IC, ode}))

the result I get from Maple12 have the following member inside it:

LambertW(_Z7, _Z)

but I do not know what are _Z7 and _Z.

Where I can find the expression of these parameters?

## Maple 12: suppress (t) with dotted derivatives...

I like the feature that permits the use of the dotted derivative, as it has the look and feel of the work that I am doing. However, when I enter, say, (x_dot + 1)^2 and invoke the expansion, I get x_dot(t)^2 +...

It's nice that Maple knows that x is a function of t, but I would like to avoid the clutter. How do I suppress the (t) so that all I see is x_dot^2?