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With your help I have a solution to a system of three equations:

(parameters are calculated on the basis of the data (for different values) - one example below)
A1=0.00002072968491, A2=0, A3=0.001946449287, A4=0.01946449287

B1=, B2=0, B3=0.0004773383613, B4=0.00004773383613

C1=, C2=0, C3=, C4=0.00009087604510

 

eqa1: = A1 * (diff (Tg (x), x, x)) + A2 * (diff (Tg (x), x)) + (A3 + A4) * tan (x) + A3 * Tg (x) + A4 * Tw (x) = 0;

eqa2: = B1 * (diff (Tw (x), x, x)) + B2 * (diff (Tw (x), x)) + (B3 + B4) * Tw (x) + B3 * Tg (x) + B4 * tan (x) = 0;

eqa3: = C1 * (diff (Tz (x), x, x)) + (C3 + C4) * Tg (x) + C3 * tan (x) + C4 * Tw (x) = 0;

 

indets ({eqa1, eqa2, eqa3}) minus {x};

res: = Dsolve (eval ({eqa1, eqa2, eqa3}) union {boundary conditions ??}, numeric);

 

for k from 0 to 20 evalf (res (k), 4); from;

c1:= 0.524:

c2:=0.05:

m: = 0;

for m from 0 to 20 and

T (m): = c1 * rhs (op (6, res (m))) + c2 * rhs (op (2, res (m))) + (1-c1-c2) * rhs (op (4, res (m))); print (m, T (m)); end to:

 

How and what type boundary conditions (I was thinking about the simplest or third type) to be able to determine the values on the y-axis on the graph. For example, the values started at -10, and ended at 10 (at a point (x, -10), (x, 10) in the coordinate system for a predetermined x, for example, from 0 to 20 which start at the point (0, -10 ) and stop at the point (20,10)). My main purpose is to collect these three solutions  to one equation T (x) = az * Tz (x) + and * Tw (x) + ag * Tg (x), and the ends of the graph, they should be in the above-mentioned points (0, -10 ) - start and (20,10) - stop.

 

Now thank you very much for the advice.

Ewa.

Hi,

I've noticed there are settings to set the type of index for spinors or gauge index in the physics package. i.e Setup(spinorindices=lowercaselatin). I also notice there is a setting for specifying the form of tetrads. 

I cannot find any further documention or examples on how to use these functions. Could anyone point me in the direction of a text or help function as to how these are implemented. 

Simple examples of things I am trying to do:

> with(Physics); Setup(spinorindices=lowercaselatin, metric = <some_line_element>)

> tetrad[`mu`,`~a`] = Matrix(<some tetrad matrix>) 

> Define(%)

I recieve the following error: invalid input: unknown uses a 2nd argument, a, which is missing.

I am hoping for a tensor that uses the metric to raise/lower the `mu` component and the minkowskian metric to raise/lower the `a` component. 

If there is further documentation that I am missing, I'm happy to check that out instead of asking lots of questions here. 

Thanks again.



This is my code for the Extended Euclidean Algorthim which should return integer l, polynomials pi,ri,si,ti for 0<=i<=l+1. And polynomial qi for 1<=i<=l such that si(f)+ti(g) = ri and sl(f)+tl(g)=rl=GCD(f,g).
The problem is, I keep getting division by zero. Also it evaluates pi = lcoeff(ri-1 - qiri) to be zero, everytime. Even when I remove this it still says there is a division of zero, which must be coming from qi:=quo(ri-1,ri, x); however I do not know why considering the requirements for the loop are that r[i] not equal zero. I really could use a fresh pair of eyes to see what I've done wrong. Any help would be greatly appreciated!!

Hi there,

Is there a way in which i can solve the following optimal control problem numerically with Maple?

 dH/dt=λ-µ H-(1-u1)β H V+δ I,

dI/dt=(1-u1)β H V-σ I,

‎dV/dt=(1-u2)k I-γ‎V,

dλ1/dt=-1+λ1µ+β‎‎V(1-u1)(λ1-λ2),‎

dλ2/dt=λ1δ+λ2σ-λ3(1-u2)k‎,‎

‎dλ3/dt=β H(λ1-λ2)(1-u1)‎‎+λ3γ.

where

u1=βHV(λ1-λ2)/A1,

u2=-λ3kI/A2,

σ = α + δ,

and

H(0)=1.7*10^8,    I(0)=0,    V(0)=400.

 

λ=5*10^5,    µ=0.003,     β=4*10^(-10),    α=0.043,    δ= 0.2                  k=6.24,       γ‎=0.65.

A1=900, A2=1000.

 

Answers and advice are very appreciated. 

Thank you all for reading.

Aylin

Hello, I'd like to use Maple to use Newton's Method in an interval to find multiple roots of 4xcos(3x)+(x-2)^2-2=0. What I have so far is:

with(Student[NumericalAnalysis]):
f := 4*x*cos(3*x)+(x-2)^2-2:
Newton(f,x=2,tolerance=10^(-4));

 

Other than trying out different initial guesses is there a way to do this?

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

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