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 For solving polynomial systems I used RootFinding[Isolate]. But after discussing the question http://www.mapleprimes.com/questions/211774-Roots-Of--Expz--1
I decided to compare Isolate and evalf(solve ([...], [...])). It seemed to me that solve some convenient. The only if in the equation there are integers as a real, they should be recorded with a decimal point. (For real solutions of this procedure should be used with (RealDomain).)  Examples:

SOLVE_ISOLATE.mw

I wonder why then the need Root Finding [Isolate]?

Maple 15.

I have a set of equations I can solve manually, but, solve fails.

restart;
eq1 := tgtX[1] = 0;
eq2 := tgtY[2] - y[2]    = m[2]*(tgtX[2]-x[2]);
eq3 := tgtY[3] - y[3]    = m[3]*(tgtX[3]-x[3]);
eq4 := tgtY[4] - y[4]    = m[4]*(tgtX[4]-x[4]);
eq5 := tgtY[2] - tgtY[1] = vy*t[2];
eq6 := tgtY[3] - tgtY[1] = vy*t[3];
eq7 := tgtY[4] - tgtY[1] = vy*t[4];
eq8 := tgtX[2]           = vx*t[2];
eq9 := tgtX[3]           = vx*t[3];
eq10:= tgtX[4]           = vx*t[4];
#
# solve the equations
eqs  := {eq1,eq2,eq3,eq4,eq5,eq6,eq7,eq8,eq9,eq10};

solvx := solve(eq10,vx);
solvy := solve(eq7,vy);
sol1  := subs(vx=solvx,{eq8,eq9});
sol2  := subs(vy=solvy,{eq5,eq6});

soln  := subs(sol1,{eq2,eq3});

soln  := subs(tgtY[2]=solve(sol2[1],tgtY[2]),soln);
soln  := subs(tgtY[3]=solve(sol2[2],tgtY[3]),soln);
soln  := subs(tgtY[1]=solve(soln[1],tgtY[1]),soln[2]);
soln  := solve({eq4,soln},{tgtX[4],tgtY[4]});

# this returns empty solution
solve(eqs,{tgtX[4],tgtY[4]});

Any ideas?

Tom Dean

Dear all;

I need your help to solve the non-square system of equation

 


restart;
with(LinearAlgebra);
 l1 := [1, 1, 1, 0, 0, 0, 0, 0, 0];

l2 := [0, 0, 0, 1, 1, 1, 0, 0, 0];

l3 := [0, 0, 0, 0, 0, 0, 1, 1, 1];

l4 := [1, 0, 0, 1, 0, 0, 1, 0, 0];

l5 := [0, 1, 0, 0, 1, 0, 0, 1, 0];

l6 := [0, 0, 1, 0, 0, 1, 0, 0, 1];

l7 := [0, 0, 1, 0, 1, 0, 1, 0, 0];

A := Matrix([l1, l2, l3, l4, l5, l6, l7]);
    # Unknown vector                    

m := [m1, m2, m3, m4, m5, m6, m7, m8, m9];
# Right hand side                  

 b = [15, 15, 15, 15, 15, 15, 15];

 

# Let the matrix equation : A m =b

1)I need your help to compute the kernel and general solution of this matrix equation

2) can we find a solution if m_k in { 2 3 4 5 6 7 8 } and each of these number appears at least once

3) If there a solution if we consider m_k in the set {0 1 2 3 4 5 6 7 8 }  and the number used exactly one

 

 

Thank you very much for your help

 

 


                     

I have a system of 16 polynomial equations in 15 variables. Independently I know there is at least a one parameter familiy of solutions to this system, so there is reason to think at least two of the equations are redundent. I would like to use Maple to decipher which of the equations are redundent, but I am unsure how to proceed.

So far I have looked at the Groebner package, and it seems like the Reduce and InterReduce commands will be useful. Say I call the set of 16 polynomials X and define a lexicographical order T on the variables. I then ask maple to compute

Reduce(X,X,T)

and receive a list with 7 zeroes and 9 polynomials. What exactly is this telling me? Does this mean that maple has used polynomial division and found that 7 of the equations are redundent?

Thanks for your help!

Hello..  I want to know if there is anny command to show the matrix of linear system.  I recently entred a 64 equations and i solved it by command solve,  but i want to show the matrix of system..  So plz. Help 

I have the system:

 

Update:

{-1/2 < 2*f*(1/53)+7*g*(1/53), 3/106 < 7*f*(1/53)-2*g*(1/53), 2*f*(1/53)+7*g*(1/53) < -37/106, 7*f*(1/53)-2*g*(1/53) < 1/2}

 

which I wish to solve over integers but isolve() gives me "Warning, solutions may have been lost and no solutions". The solutions exist and are {[f =0, g = -3] || [f = 1, g = -4], [f = 1, g = -3] || [f = 2, g = -4]}, but I cannot obtain them with Maple. Could you tell me what is wrong and how I should treat this kind of problems in the future, please.

Mathematica 10.0

Reduce[{-1/2 < 2*f*(1/53) + 7*g*(1/53), 3/106 < 7*f*(1/53) - 2*g*(1/53), 2*f*(1/53) + 7*g*(1/53) < -37/106, 7*f*(1/53) - 2*g*(1/53) < 1/2}, {f, g}, Integers]

(f == 0 && g == -3) || (f == 1 && g == -4) || (f == 1 &&
   g == -3) || (f == 2 && g == -4)

 

Maple

isolve({-1/2 < 2*f*(1/53)+7*g*(1/53), 3/106 < 7*f*(1/53)-2*g*(1/53), 2*f*(1/53)+7*g*(1/53) < -37/106, 7*f*(1/53)-2*g*(1/53) < 1/2});
Warning, solutions may have been lost

 

Sorry for disturbing you. I am wondering if there is an easier approach in Maple that could convert a system of second order differential equations into matrix form. Of course, we could do it by hand easily if the degrees of freedom is small. I would like to know if we could use Maple to do so. 

Here is an example with 6 degrees of freedom: the variables are u, v, w, alpha, beta and gamma. And, this is a uncoupled system.

Vector(6, {(1) = 2*R^2*(diff(w(t), t))*Pi*Omega*h*rho+R^2*(diff(u(t), t, t))*Pi*h*rho-R^2*u(t)*Pi*Omega^2*h*rho = 0, (2) = R^2*(diff(v(t), t, t))*Pi*h*rho = 0, (3) = -2*R^2*(diff(u(t), t))*Pi*Omega*h*rho+R^2*(diff(w(t), t, t))*Pi*h*rho-R^2*w(t)*Pi*Omega^2*h*rho = 0, (4) = (1/4)*R^4*Pi*(diff(alpha(t), t, t))*h*rho+(1/12)*R^2*Pi*(diff(alpha(t), t, t))*h^3*rho+(1/6)*R^2*Pi*(diff(gamma(t), t))*Omega*h^3*rho-(1/12)*R^2*Pi*alpha(t)*Omega^2*h^3*rho = 0, (5) = (1/2)*R^4*Pi*(diff(beta(t), t, t))*h*rho-(1/2)*R^4*Pi*beta(t)*Omega^2*h*rho = 0, (6) = (1/4)*R^4*Pi*(diff(gamma(t), t, t))*h*rho+(1/12)*R^2*Pi*(diff(gamma(t), t, t))*h^3*rho-(1/6)*R^2*Pi*(diff(alpha(t), t))*Omega*h^3*rho-(1/12)*R^2*Pi*gamma(t)*Omega^2*h^3*rho = 0});

The objective is to reform it into matrix form : M*diff(X(t), t, t)+C*diff(X(t), t)+K*X(t)=F.

Thank you in advance for taking a look. 

 

It returns unevaluated.  The solution is x=-ln(3),y=0.  In fact it doesn't give a solution even if the solution is provided as the initial point.  The value of Digits doesn't seem to make a difference.

(Tested Maple 2015.2 Macintosh and Maple 2015.1 Linux)

can we solve analytically a system of non-linear algebraic equation? my system is like:

 

b1 = a x + b y + c z

b2 = d x2 + e y2 + f z2

b3 = g x3 + h y3 + k z3

 

thanks

Dear Maple users

In order to solve a problem in Biology, I have come across four equations with three unknowns, making it overdetermined. The equation system does not have any specific solutions, but since the equations can be considered containing errors, I am looking after the best possible solution - which will minimize the coefficients in the original equation system. My question is twofold:

1. Does there exist a specific Mathematical Theory to handle non-linear equation systems of this type?

2. Which command in Maple can solve it?

 

 

Regards,

Erik

 

Can Maple simplify these DE's by eliminating the d/dt VL(t) by taking the derrivative of the bottom equation and substituting in the first one? 

I solve a linear system of equations which is rank deficient. Naturally, when Maple solves it symbolically, it chooses some of its variables to use them as a basis to express the solution. 

In a specific problem I'm solving, the basis chosen by Maple is -very- smart, showing a good exploitation of the problem structure. 

I'm curious as to what kind of factorization is used by default, or if there's a lot of by hand "black magic" involved, what are its general characteristics. 

 

Best regards

Claudio

how to calculate the polynomial map for a system of  polynomials

assume system of polynomial is in terms of a,b,c

how to find polynomial map

(r - something in terms of a,b,c)

(u - something in terms of a,b,c)

(v - something in terms of a,b,c)

 

A lot of my life is at the moment spent using solve to solve systems of equations, and then trying to weed through the solutions maple gives to find the ones I am interested in. Specifically i'd like to have a program that can weed through the solutions and eliminate those that include equalities of the  form p[i]=-p[j] or p[i]=0  where i and j are integers (or equalities of that form with the letter q replacing p). Specifically i don't want to exclude equalities of the form p[i]=-p[j]*something+something else-another thing.... as they can be useful (or equalities of that form with the letter q replacing p).

Here is a (simple) example of the kind of equations I am likely to be solving and their output from solve:
A := solve([p[1]*p[2]*p[3] = q[1]*q[2]*q[3], p[1]+p[3] = q[1]+q[3], p[2]^2+p[3]^2 = q[2]^2+q[3]^2])

I have some code which gets rid of solutions where one variable is set to 0 

with(ArrayTools);
GetRidOfDumbSolutions := proc (sols)
local Nsols, Npars, GoodSol, GoodSols, GoodSolsCounter, i, j;
Nsols := numelems(sols); Npars := numelems(sols[1]);
GoodSols := []; GoodSolsCounter := 0;
for i to Nsols do
GoodSol := 1;
for j to Npars do
if IsZero(rhs(sols[i, j]))
then GoodSol := 0
end if
end do;
if GoodSol = 1 then
GoodSols := Concatenate(1, GoodSols, sols[i])
end if
end do;
GoodSols
end proc

but i can't see how (in maple) to detect an expression of the form p[i]=-p[j] especiall if that is being written in 2-d math. (i don't quite understand the different maths environments or how to convert from one to another or to string)

Dear Maple T.A. users

I have just begun using Maple T.A. I have access to a number of questions, some of which involves placing points in a coordinate system. It works for most students, but for a few, including myself, it doesn't work. I am not able to place those points in the coordinate system at hand when leftclicking. What can be the reason for this issue?

Erik

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