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Hi everyone!

I wrote simple program which fits experimental result. I know that experimental points should be fitted with this function — Te=exp(a*X+b), where "a" and "b" are parameters. "X" — vector of independent variable, "Te" — vector of dependent variable.

My question is: can maple estimate error of my fitting? I want to obtain "a±Δa" and "b±Δb".

My program: Profile.mw

P.S. Excuse me, for my english. It isn't my native language.

I got a problem with a difficult ode,the commands are below.

restart;
sys := 1.*(diff(x(t), t, t)) = piecewise(b(t) = 1, 0, 1003.0-1000.*x(t)-30.*(diff(x(t), t))-25.*signum(diff(x(t), t)-.1)-.3*signum(diff(x(t), t))*exp(-2*abs(diff(x(t), t)))), x(0) = 1, (D(x))(0) = 0;
mu := 100;
stick := [diff(x(t), t) = .1, b(t) = piecewise((1000.-1000.*x(t))^2 < 10000, 1, 0)];
slip := [[0, 10000 < (1000.-1000.*x(t))^2], b(t) = 0];
sol:=dsolve({sys,b(0)=0},numeric,discrete_variables=[b(t)::float],events=[stick,slip],event_maxiter=1000000,output=listprocedure,maxfun=0,range=0..8);

any advice is appreciated.

In Maple 16  (obviously, the result must be positive):

VectorCalculus:-int(x+y, [x, y] = Sector(Ellipse((1/4)*x^2+(1/9)*y^2-1), 0, (1/2)*Pi));

                                                                        -2

Probably, this error occurs only in the latest versions, as in Maple 12 the output is correct. It would be interesting to know the reason for this behavior.

 

I have to calculate the data in JSON format and export the result back to JSON.

It would be greate if there is any JSON package for Maple.
---

Also, I use`ExportMatrix` to export the result to CSV format.

But there are some comma (`,`) in the result content and `ExportMatrix` does not handle it well.
Is there any solution for export data to CSV file in my situation?

Thanks.

 

Hi,

i need to remove all the elements from a matrix that are almost zero, for example, from this matrix:

matrix = (Matrix(2, 2, {(1, 1) = 1/1000000000000000000, (1, 2) = 1, (2, 1) = 1, (2, 2) = 1}))

i need to remove the smallest element, so the final matrix will be like:

matrix = (Matrix(2, 2, {(1, 1) = 0, (1, 2) = 1, (2, 1) = 1, (2, 2) = 1}))

Is there a simple way to do that? Maybe forcing Maple to use number above a threshold?

 

Thanks

 

Hi there,

 

I'd like to solve 7th order implicit simultaneous equation such as below, so I tried to do it by solve command.

However the calculation wasn't over although three hours passed.

 

eq1 := f1(a,b,c,d,e,f,g) = 0;

eq2 := f2(a,b,c,d,e,f,g) = 0;

.

.

.

eq7 := f7(a,b,c,d,e,f,g) = 0;

 

Just for your information, the eq1 and eq6 are written as follows specifically.

eq1 := -a-b-c-d-e-f-g+0.501857 = 0

eq6 := a*b*c*d*e*f+a*b*c*d*e*g+a*b*c*d*f*g+a*b*c*e*f*g+a*b*d*e*f*g+a*c*d*e*f*g+b*c*d*e*f*g+a*b*c*d*e+a*b*c*d*f+a*b*c*d*g+a*b*c*e*f+a*b*c*e*g+a*b*c*f*g+a*b*d*e*f+a*b*d*e*g+a*b*d*f*g+a*b*e*f*g+a*c*d*e*f+a*c*d*e*g+a*c*d*f*g+a*c*e*f*g+a*d*e*f*g+b*c*d*e*f+b*c*d*e*g+b*c*d*f*g+b*c*e*f*g+b*d*e*f*g+c*d*e*f*g-0.5281141885e-3+1.01894577*10^(-12)*I = 0

 

And the program code I used is:

solve([eq1,eq2,eq3,eq4,eq5,eq6,eq7],[a,b,c,d,e,f,g]);

 

Here is the specification of my computer.

OS: Windows 7 Enterprise 64bit

CPU: Intel Core i7-3520M 2.90 GHz

Memory: 4.00 GB

 

How can I handle this problem? Is the specification not enough to solve the equation? Do I need to leave my computer more and more time?

Any help would be appriciated.

matrix solution...

October 22 2014 mahdi1625 10

the following program dont work

a := 1;
b := 2;
c := 3;
d := 4;
eq1 := a*x[1]-b*x[2] = 0;
eq2 := c*x[2]-d*x[1] = 3;
dd := fsolve({eq1, eq2}, {x[1], x[2]});
evalf(sin(dd[1]));

 

wouldyo please help me?

 

Hi,

This may be just my lack of maple syntax, however I cannot seem to find a way to add upper indicies in tensors (without first converting them to some other object, array, matrix etc)

In the physics package an example is just the metric tensor. 

I am trying to do something like this:

 

with(Physics);

add(g_[~mu,2], mu=1..2) 

Is there an easy way of summing upper indicies? Obviously lower indicies work, because the add/sum command recognizes the variable to iterate. 

Thanks in advance,

Age

 

 1) find  the direction in which f(x,y) increases most rapidly at the point P(1,2), and find the maximum rate of increase
of f at P.

Interpret 1) using the graph of f.

 

Let f(x,y) = 2+x^2 +1/4*(y^2)

Download Problem_#7_Instructor_#4.mw

 

First, thanks for taking the time to read this post. I'm trying to solve a system of equations, that consist of some complicated arguments. I've tried simplifying it a number of ways, and I've even tried using fsolve({...},{...}), but it will not yield any results. It only gives the response "Warning, solutions may have been lost". The link to the worksheet is posted above. I'm new to this program and forum, so I was not sure whether to upload the link or the contents (I can send the other if necessary.). Your help is much appreciated.

 

Thanks,

Stephen

Having solution of an inequations system, is there a way/function/algorithm to find a particular numeric solution (as simplex[minimize] can do) ?

ex:

Q := {1 < x - y, x + y < 1};

R := solve(Q);

      { x < 1 - y, y < 0, y + 1 < x }

manually it's easy to find some numeric solutions:


      y = -1, x = 1
      y = -2, x = 0

but I need an automatic way.

Thank you for your help
s.py

 

Hi,

I need to build a multibody model in MapleSim 6.4 in which with few global parameters I can describe all the other parameters. In other words the final user will enter this few parameters, that are coordinates of specific points, and then the model will calculate all the relative distances on the base of those coordinates.

The problem is that if I apply trigonometric function and square root (like in the screenshot) the model is not calculating any value. Is it possible to make those calculculations?

 

this is the model (don't worry about the nonsense plots, it's because it's not ultimated):

DWS.msim

 

 

Thanks.

 

a+a*c

a+a*b

a+b+c

assume system of polynomials are above, how to test whether inverse exist

and find inverse of them

 

Hi all

I want to produce following c_nm's(which are differentiation based formula) . assume that N and M are known and f(t) is arbitrary. also n=1,2,...,N and m=0,1,..,M-1

how can we do this?

regards


Mahmood   Dadkhah

Ph.D Candidate

Applied Mathematics Department

This Maple 13 so maybe things have been fixed. Here are four points whose convex hull consists of three points. Sometimes the result comes out correct, more often it does not. With numbers this small it shouldn't be an issue of roundoff. But changing digits changes the result!

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