## How to solve the problem of least square ?...

i need to solve the equation in method in least square; i have one equation e.g.f(x)=a*x^2-b*x-c, but i need use it two times in one equation,like g(x)=f(x1)-f(x). f(x1) put the value x1 in equation f(x),the behind is not change.so the equation like this : a*x1^2-b*x1-c-a*x^2-b*x-c if i input the equation g(x):=f(x)-f(x)the input the value a,b,c.got the 0. it's not my need. who can tell me how to solve the problem?

## Visualization of a linear system of more than one ...

Hi people, I would like to know how to obtain in maple (to add this in a variable in mapleTA) the next thing: a system like this: {x+2y=0, x+4y+3z=5, x+y+z=0} in a good presentation way, I mean, If I do MathML:-ExportPresentation({x+2y=0, x+4y+3z=5, x+y+z=0}) and I use the resultant code in mapleTA, I obtain the system in a inline way, but I want it like this: x+2y=0 x+4y+3z=5 (here a big "}" englobing all) x+y+z=0 How is it possible using only maple? Thanks

## Generating unevaluated MathML...

I want to generate MathML code. I'm using Maple 9.5. However I want the generated code not to evaluate the expression. For example:

> codegen[MathML](5^4);
<math xmlns='http://www.w3.org/1998/Math/MathML'>
<semantics>
<mn xref='id1'>625</mn>
<annotation-xml encoding='MathML-Content'>
<cn id='id1' type='integer'>625</cn>
</annotation-xml>
<annotation encoding='Maple'>625</annotation>
</semantics>
[/itex]

while what I want is:

<math xmlns='http://www.w3.org/1998/Math/MathML'>
<semantics>
<mrow xref='id3'>
<msup>
<mi xref='id1'>5</mi>

## Printing in Maple 10...

Hi When I try to print in Maple 10.05 having set the zoom factor to below 100% (e.g. 75%) the print is still in 100% zoom. How do I print using a smaller zoom? This was possible in Maple 10 Classic and Maple 9.5 By the way, I am using Ubuntu Linux 6.06 Regards

## Maple returns e instead of exp...

Hi all.. I am probably overlooking a switch or setting in Maple(10)Win XP, but when I do a calculation such as: yh:=c1*x1*exp(-1.5*t)+c2*x2*exp(-1.44*t); Maple returns: yh:=c1 x1 (e)^((-1.5000 t))+c2 x2 (e)^((-1.4400 t)) Which is correct but Maple does not recognize the (e)^(-1.44*t) as the exponential when I try to use it in future calculations. Is there a setting I have missed or is this how Maple handles exponentials? TIA Larry Ciak aka malt_master@comcast.net

## Complex differential equations...

Hi, I am trying to solve a first order differential equation numerically using dsolve. The equation is of the form dx/dt = k1 x + k2 |x|^2 x where x(t) is a complex valued function and k1 and k2 are complex constants. I get the following warning/error from maple10 Warning, abs is not differentiable at non-real arguments For this equation dsolve only gives me the solution for relatively short times (t ~1 or 2) and I know there is a solution valid at large times >>1. Obviously I could cast this equation into a system of 2: one for the real part and the other for the imaginary part.

## Simultaneous Algebraic Equations...

Given N-1 independent (not necessarily linear) equations in N variables, how do I tell Maple to find solutions in terms of a specific variable? For example: with(RealDomain); eq1:=x-1=a*cos(theta); eq2:=x+1=a*sin(theta); I want to find a and theta in terms of x: a=sqrt(2*x^2+2), theta=arctan((x+1)/(x-1)) solve({eq1,eq2},[a,theta]) appears to give me solutions based on elimination of x.

## Hiding the axis' scale when plotting?...

Hello! Another newbie question. How do I prevent Maple from displaying the actual numbers on the x-axis and y-axis in a plot? I've looked around in Help, but couldn't find anything useful... Thanks for your interest! Carolus

## problem with Maple10...

Hi guies, my Maple is out of order because my "kernel connection is not available" and Maple is closed by "mserver.exe"; my firewalls are stopped when I open Maple. Before this problem Maple did'nt find the dll:"libgmp-3.dll".However I reinstalled Maple. What can I do? Thanks

## Plot a function against another function?...

I have two functions describing the physics of gamma radiation. I want to plot one function in terms of the other, i.e., set my x-axis to one function, and my y-axis to the other, to see there relation as there values increase. How do I do that? Thanks.

## Why does this procedure call fail??...

Hi: The follwoing snip contains two identical procedures. The first call fails, the second call works. Why?? restart; test1:=proc(a,b,c); with(combinat,permute); perm1:=permute([a,b,c],3); end proc; Warning, `perm1` is implicitly declared local to procedure `test1` test1 := proc(a, b, c) ... end; test1(a,b,c); permute([a, b, c], 3) test2:=proc(a,b,c); with(combinat,permute); perm2:=permute([a,b,c],3); end proc; Warning, `perm2` is implicitly declared local to procedure `test2` test2 := proc(a, b, c) ... end; test2(a,b,c);

## Using fopen problem...

I would like to read a data file that is located in "My Documents" folder using the open command, but maple cannot find the file. The file name is data1.txt and I think the complete folder name is c:\Documents and Settings\dhalpern\My Documents I have tried INP := fopen("C:\Documents and Settings\dhalpern\My Documents\data1.txt",READ,TEXT); but I get the following error message. Error, (in fopen) file or directory does not exist I have checked that the file and directory DO exist. If I place the data file in c:\ then I don't have any problems but I would prefer to have my files in My Documents.