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    Now we turn to an example of the usage of the Dragilev method with Maple. Let us consider the curve
    from
    http://www.mapleprimes.com/questions/143454-How-To-Produce-Such-Animation .

    Its points can be found by the Dragilev method as follows.

     

    This is an effective method of solving systems of  N nonlinear and nonalgebraic equations in N+1 real-valued variables:
    F(x)=0, where F=(f1,f2,..., fN) and x=(x1,x2,...,xN+1). (1)               
                                                                      
    All the functions fj(x) are assumed to be continuously differentiable in some domain D in R^(N+1).
    In general, such systems have an infinite set of the solutions which form a space curve in R^(N+1).
     The Optimization and DirectSearch solvers have difficulties with it.
    The idea of the Dragilev method consists in the following. Let us assume that the space curve (1) can be parametrized through the  parameter t
    which can be taken as the  length of the arc (for example, see http://en.wikipedia.org/wiki/Curve ).
    That presentation provides to avoid the difficulties associated with self-intersections and singularities.
    We will obtain the coordinates of the points of the space curve under consideration as the solution
    of the Cauchy problem for certain system of ODEs. We put the coordinates of a known point of (1) as the initial conditions.
    The system of ODEs is obtained by the differentiation  with respect to t:

    We treat (2) as a linear system in the derivatives diff(xj(t),t),j=1..N+1. In general, its solutions form an infinite set.
    We choose the  solution of (2) as follows. We put diff(xN+1)= -Determinant(Matrix(n, (i,j)->diff(fi(x),xj))).
    This is one of the key points of the method under consideration.
    Next, we find diff(xj,t), j=1..N. At last, we numerically solve that system of ODEs, obtaining an array of points.
     The general case of a system of N nonlinear  equations in N variables
    G(y)=0, where y=(y1, y2, ..., yN), G=(g1,g2,..., gN) (3),
    is reduced to the previous one by homotopy. We choose a point y0= (y01, ..., y0N) and consider the system
    G(y)- v*G(y0)=0 (4)
    of N equations in N+1 variables (v is taken as  a dummy variable). Changing v from 1 to 0, we arrive to (3).
    We don't consider any mathematical justification of the above pattern here as that does not deal with Maple.
    I would like to point out the sites

    http://forum.exponenta.ru/viewtopic.php?t=3892 and
    http://forum.exponenta.ru/viewtopic.php?t=11284 , where the Dragilev method is discussed. Unfortunately, in Russian.
    The googling of "Dragilev" and "Draghilev" does not produce many info.
    A short biographical sketch: Dr. Anatoliy Vladimirovich Dragilev (1923 - 1997) was a professor at  Rostov State University in Russia.
    See his articles here: http://www.mathnet.ru/php/person.phtml?&personid=32359&option_lang=eng and
    http://www.zentralblatt-math.org/zmath/en/search/?q=au%3A%22dragilev%2C%20a*%20v*%22 .
     

    I am very grateful to Professor Alexey B. Ivanov, who is an enthusiast of the Dragilev method, for the very useful discussions.

    The new option added to MaplePrimes about two hours ago----to show Answers by date----only shows the Answers in reverse chronologocal order. That's ridiculous! Even more so with the comments still being in forward chronological order. The reason that people have requested date order so vehemently is to preserve the continuity of conversation. With the reverse chronological order, the continuity is worse than before.

    Earlier this afternoon we made an update to MaplePrimes to introduce some new features and to squash a few bugs.

    The primary purpose of the update was to improve the context around how replies and answers are entered on MaplePrimes. The most significant change you will notice here is that submission/edit boxes now appear inline  under the specific message you are replying to, instead of at the bottom of each page.

    Other improvements include:

    Maple 17 adds several new visualizations in Graph Theory as well as updates to inequality plotting and visualizing branch cuts in mathematical expressions.  In preparing the “what’s new” pages for Maple 17, we decided to showcase several of these plots alongside some of our other favourites.

    The following file contains code to create most of the “what’s new” plots, as well as some quick tips and techniques for using the ColorTools package to enhance your plots:...

    Dear Maple Users

    I am mainly in favor of the new rules concerning subscripts. Using Ctrl+-- (double underscore) it is pretty straight forward to get a literal subscript and it displays much better in the palette Variables than was the case i Maple 16. Also the purple coloring of a variable containing a literal subscript makes sense, because it can be distinguished from the usual subscript (now Ctrl+shift+-). Good that you can remove the coloring in the View Menu (Atomic Variables...

    I'm pleased to announce that Maplesoft is working with the team at DigiArea, Inc. to further develop and enhance their Integrated Development Environment (IDE) for Maple. When we're done, the IDE will be distributed under the Maplesoft brand, and available for purchase through our Web Store.

    The IDE doesn't replace Maple's current user interface, but is instead a separate, specialized environment for developing medium- to large-scale Maple libraries. It includes tools...

    Dear friends,

    I am reporting with a brief comment concerning the integral int(1/(1+x^a), x=0..infinity) with a>=2 a real number. This was evaluated here.

    Now Maple 15 (X86 64 LINUX) will quite happily compute this in its most simple form involving the sine when a is not a positive integer or a rational number. If it is, however, a beta function term results,...

    Animation spatial lever mechanism on the basis of one of the sets of solutions of systems of polynomial equations. The Draghilev method. MECAN123.mw 

    http://hostingkartinok.com/show-image.php?id=fe0ac50ab68d6ab66a3469394654a260

    In Maple 17, the Student MultivariateCalculus package has been augmented with fifteen new commands relevant for defining and manipulating lines and planes. There already exists a functionality for this in the geom3d package whose structures differ from those in the new Student packages. Students...

    I propose a different proof of this remarkable identity (see  http://www.mapleprimes.com/posts/144499-Stunningly-Beautiful-Identity-Proved ) in which  directly constructed a polynomial, whose root is the value of LHS, and this is expressed in radicals.

    For the proof, we need three simple identities with cubic roots (a, b, c -any real numbers):

    Every year at Maplesoft, we continue to pursue our mission of making powerful computational mathematics easily accessible within a friendly environment. Maple 17 is no exception: Hundreds of new algorithms, from differential equations to statistics to signal processing, continue to keep Maple ahead of the curve. At the same time, a wealth...

    I present this proof-in-Maple not just for its own sake, but because I think that it illustrates effective techniques for working with complicated algebraic numbers.

    Proof...

    Never before has the educational landscape been changing as fast as it is today, driven by a new generation of students who are growing up with instant access to on-demand information. This generation relies on ubiquitous network access and takes for granted technology that permeates every aspect of their lives. Phones and tablets are everyday companions and are used to connect with their peers, take classroom notes and research school projects. Beyond being mere consumers...

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