## Variance-Covariance matrix

by:

Hi all,

I created a fit function (y = a*x^b + c) from a list of x and y experimental data. I would like to calculate the variance-covariance matrix of the 3 coefficients a, b and c but I found that the command variancecovariancematrix works only for the linear fitting. Can you help to solve this problem easily?

Thanks

## Can't use Maple without an internet connection

by:
Topic title pretty much says it all. I can only use Maple (ver. 13.02 aka latest) when I have internet access. Without I can however open the program, but I'm not able to calculate anything or change any settings. Anyone know a fix to this problem?

## IVP

by: Maple

I solved IVP of ODE with solutions x(t),y(t),z(t) numerically.x(0)=y(0)=0,z(0)=0.25

How can I get the coefficients of the initial values in x(t)

i.e  assume the solution

x(t)=e1(t)x(0)+e2(t)y(0)+e3(t)z(0)+e4(t)

how can we get :

e1(t),e2(t),e3(t) and e4(t)

by: Maple

I recieved this comment on an older post of mine, and I was going to post a reply, but I noticed my reply was pretty long, and I was also missing a post for last friday, so I figured I'd cheat and make the reply a blog post of its own.

## How to stop searching?

by:

Some key words will take a lot time when search for something by text

It's fast when search for something by topic in Help system

Can I stop the search progress?

Maybe the search function canbe developed,more quickly.

## call stack

by: Maple

Very few people would ever need this, I think, even while programming. But sometimes the details of the call stack are just what one wants.

So, for example,...

```> h:=proc(x)
>   debugopts('callstack');
> end proc:

> m:=module() export f; local g;
>   f:=proc(x)
>     g(x^2);
>   end proc:
>   g:=proc(x)
>     global h;
>     h(x^3);
>   end proc:
> end module:

> m:-f(a);
[DEBUGSTACK, h, `debugopts('callstack')`, [a^6...```

## flagging posts

by:

Perhaps it would help to be able to flag not only replies but also parent forum and blog posts.

## fsolve values

by: Maple
I've been working with fsolve and I'm having the following issue: fsolve({dif_Fliq=((nFsol-nFliq)/(psi_sol-psi_liq)),dif_Fliq=dif_Fsol},{psi_sol=0.1..0.9,psi_liq=0.1..0.9}); {psi_liq = 0.4447971078, psi_sol = 0.3459845910} how do I get the value of psi_liq and psi_sol and assign them to a different variable without having to copy the whole thing? i.e. if I use the following command assign(result_liq,psi_liq); I get result_liq=psi_liq = 0.4447971078 not what I want result_liq = 0.4447971078 I also tried: result_liq:=psi_liq and I ended up with the same result

## Making a dash for it

by: Maple

An attempt at question 2 of the xkcd Velociraptor Math problem (mentioned on this blog post). The parameters and events facilities of

## Classic on XP64

by: Maple

There is no released Classic interface to accompany the 64 bit version of Maple (12, 13) for the 64 bit Windows XP64 operating system. Personally, I prefer running the Standard over the Classic interface, although sometimes I miss common subexpression display for lengthy symbolic output.

The Maple Classic interface appears to talk to the Maple kernel only over a socket (or similar), and the...

## BUG: Plots from the command line.

by:
Hi. I run Maple on 64-bit linux. I have tried to run the same commands from xmaple and maple I do not get the same result. I would very much like to be able to create postscript graphs from the command-line. However the result of the commands at the bottom of the screen is a black graph, which is NOT logarithmic. However when I run the same commands from the xmaple, the results work perfectly - a red graph on a logarithmic plot. The commands are: plotsetup(ps, plotoutput="graph.ps"): plot(exp(x), x=1..20, color=red, axis[2]=[mode=log]);

## The Teacher Resource Center

by:

As many of the users on MaplePrimes are instructors, I thought it appropriate to let everyone know about a new resource available on the Maplesoft web site called the Teacher Resource Center.

## Multi-threading – or How I Learned to Stop Worrying...

by:

Dual- and quad-core PCs are now ubiquitous.  While making your operating system a better multi-tasking environment, they’ve had a limited effect on the code that most technical professionals write.  This is largely because of the perceived difficulty of parallel programming.   The evolution , however, of high-level languages that support multi-threading throughout the 90s and beyond, removed the need to manage threads at the low level, allowing engineers to concentrate on what part of the algorithm could be run in parallel.  Given the ever-increasing complexity of systems that have to be simulated, multi-threaded programming can offer significant time savings for many the problems that can be easily parallelized (and for which time-savings of parallelization outweigh the overhead).

## It's a Small World

by:

It’s a small world, but there are still too many borders.

I’ve recently become a fan of country music.  It amazes and amuses my wife and children, but I find that country music tells stories that contain some very basic truths.

Brad Paisley sings a song named “Welcome to the Future”.  He begins that song by telling his grandfather’s story of being a soldier in the Philippines fighting the Japanese during World...

## New MaplePrimes: Reputation and Badges

by:

As most users of MaplePrimes are aware, we currently reward participation with a number that indicates Maple Rank. So every time someone posts a forum comment, for example, they are awarded 1 point. This number gets appended to user names and it has become a way to immediately recognize a person’s ‘prestige’ within MaplePrimes.

 First 138 139 140 141 142 143 144 Last Page 140 of 289
﻿