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Hello,

From a simulation software, I obtain in a matlab file my differential equations in the following way :

C_p_e = C_state/C_c;
C_p_f = I_state/I_i;
R_p_e = R_r*C_p_f;
I_p_e = (Se_p_e-R_p_e)-C_p_e;

For theses expressions, I would like to do two operations :
1) Transform it into equations
2) Conduct substitutions so as to change the names of the variables with nicer names.

For this objectives, I could do with the following code:

restart;
eq1:=C_p_e = C_state/C_c;
eq2:=C_p_f = I_state/I_i;
eq3:=R_p_e = R_r*C_p_f;
eq4:=I_p_e = (Se_p_e-R_p_e)-C_p_e
allsubs:= proc(XX )
subs(C_p_e=fs(t),C_p_f=v(t),R_p_e=fd(t),I_p_e=fm(t),C_c=1/k,I_i=m,R_r=c,Se_p_e=fe(t),I_state=int(fm(t),t),C_state=int(v(t),t),XX)
end proc:
eq1_a:=allsubs(eq1);
eq2_a:=allsubs(eq2);
eq3_a:=allsubs(eq3);
eq4_a:=allsubs(eq4);

Now, I would like to automatisation the creation of the equations eq1, eq2, eq3, eq4. For the moment, to create these equations, I have done copy/ paste from matlab.

But, I would like to create these equations eq1, eq2, eq3, eq4 with a automative process from my matlab equations. The reason comes from the fact that I would like to make the same work on bigger system which are composed with numerous equations.

How can I create equations labeled eq1, ...eqn from a list of expressions from matlab ?

Thank you for your help

i am very new with Maple.

I have the following two equations:

x1=a-y1-d*y2;

x2=a-y2-d*y1;

I wish to express the first equation in terms of y1 and x2, so that

x1 = c - b*y1+d*x2;

where c=a-a*d and b=1-d^2. How can I get maple to rearrange the original equation x1 in term of y1, x2, c and b? 

 

hello

took this problem from a uk tv program.

4 dancers are initially at the 4 corners of a square, edge length 4 meters. every dancer moves towards the person on their left.

i want to know the equations of the spiral. the arc length of each path should be 4m.  also an animation of the 4 spirals would be great. 

dance.mw

under the heading "more spirals" the closest one is r(t)=1/t (decreasing modulus)

http://mathematische-basteleien.de/spiral.htm

 

       Calculation of RSCR mechanism as a  solution to underdetermined system of nonlinear equations.  

 

RSCR.mw

 

https://vk.com/doc242471809_376439263
https://vk.com/doc242471809_408704758

Hi, I have 10 equation system and 10 unknown variables. I however, want to reduce the equations to 2 with two unknowns. I'm wondering how this could be done in maple. The variables are Y, q, yd, y*, yx, H,  pd, w, P and Pv. I intend to solve the equations for Y and w. 

Thanks in advance for your help. The maple file has also been attached.

 

Regards

Small_Open_Economy.mw

 

hi guys , i have this warning for solving a complicated equation with 7 parameters. how can i overcome to this warning ?

 


odesys := {(1/4)*(-4*r^(2+p+a)*p*a-11*r^(2+a+c)*a*c-4*r^(2+p+c)*p*c+22*r^(2+a+n)*a*n+8*r^(2+p+n)*p*n-22*r^(2+a+c)*a+8*r^(2+p+a)*p-8*r^(2+p+c)*p+22*r^(2+b)*b+32*r^(2+p)*p^2+32*r^(2+p)*p+22*r^(2+b)*b^2+22*r^(2+2*a)*a+65*r^(2+2*a)*a^2-8*r^(2+p+c)*p^2+8*r^(2+p+a)*p^2-22*r^(2+a+c)*a^2)/r^4+(1/4)*(4*r^(a+n)*n^2-2*r^(n+c)*n*c-4*r^(n+c)*n^2+3*r^(2*n)*n^2-4*r^(a+c)*c+8*r^(a+n)*n+4*r^(2*c)*c-8*r^(n+c)*n+4*r^m*m^2-4*r^d*d+8*r^m*m+4*r^m-4*r^d)/r^2}

{(1/4)*(-4*r^(2+p+a)*p*a-11*r^(2+a+c)*a*c-4*r^(2+p+c)*p*c+22*r^(2+a+n)*a*n+8*r^(2+p+n)*p*n-22*r^(2+a+c)*a+8*r^(2+p+a)*p-8*r^(2+p+c)*p+22*r^(2+b)*b+32*r^(2+p)*p^2+32*r^(2+p)*p+22*r^(2+b)*b^2+22*r^(2+2*a)*a+65*r^(2+2*a)*a^2-8*r^(2+p+c)*p^2+8*r^(2+p+a)*p^2-22*r^(2+a+c)*a^2)/r^4+(1/4)*(4*r^(a+n)*n^2-2*r^(n+c)*n*c-4*r^(n+c)*n^2+3*r^(2*n)*n^2-4*r^(a+c)*c+8*r^(a+n)*n+4*r^(2*c)*c-8*r^(n+c)*n+4*r^m*m^2-4*r^d*d+8*r^m*m+4*r^m-4*r^d)/r^2}

(1)

res := op(odesys);

(1/4)*(-4*r^(2+p+a)*p*a-11*r^(2+a+c)*a*c-4*r^(2+p+c)*p*c+22*r^(2+a+n)*a*n+8*r^(2+p+n)*p*n-22*r^(2+a+c)*a+8*r^(2+p+a)*p-8*r^(2+p+c)*p+22*r^(2+b)*b+32*r^(2+p)*p^2+32*r^(2+p)*p+22*r^(2+b)*b^2+22*r^(2+2*a)*a+65*r^(2+2*a)*a^2-8*r^(2+p+c)*p^2+8*r^(2+p+a)*p^2-22*r^(2+a+c)*a^2)/r^4+(1/4)*(4*r^(a+n)*n^2-2*r^(n+c)*n*c-4*r^(n+c)*n^2+3*r^(2*n)*n^2-4*r^(a+c)*c+8*r^(a+n)*n+4*r^(2*c)*c-8*r^(n+c)*n+4*r^m*m^2-4*r^d*d+8*r^m*m+4*r^m-4*r^d)/r^2

(2)

SOL1 := solve(identity(res = 0, r), {a, b, c, d, m, n, p})

Warning, solutions may have been lost

 

``


Download sol.mw

thanks

Hello,

This is the system of equations in term of sin and cos. I have used the command "solve" in Maple but it yielded only 2 solutions. I've tried to use with(RealDomain): It yielded more solutions but most of them were wrong.

 

 

f1 := -8100+(-30+70*cos(t1)-40*cos(t2))^2+(-70*sin(t1)+40*sin(t2))^2

f2 := (-20-80*cos(t3))^2+(-15+70*cos(t1)+10*cos(t1+t))^2+(-70*sin(t1)-10*sin(t1+t)+80*sin(t3))^2-5625

f3 := (-20-80*cos(t3))^2+(15+40*cos(t2)+10*cos(t1+t))^2+(-40*sin(t2)-10*sin(t1+t)+80*sin(t3))^2-5625

f4 := 10*cos(t1+t)*(30-70*cos(t1)+40*cos(t2))-10*sin(t1+t)*(70*sin(t1)-40*sin(t2))

 

Anybody know how to solve this system of equations to get the full set of roots?

Thank you very much in advance.

Hi .please help me for solve this nonlinear equations , that attch below

thanks a lots.....

 

 

dsys3 := {8*(diff(f2(x), x, x, x, x))+9*(diff(f2(x), x, x))+10*f2(x)+11*(diff(f1(x), x, x, x))+12*(diff(f1(x), x))+13*(diff(f3(x), x, x))+14*f3(x)+f3(x)*f3(x)+(diff(f3(x), x))*(diff(f3(x), x))+(diff(f3(x), x, x))*f3(x) = 0, 16*(diff(f3(x), x, x, x, x))+18*(diff(f3(x), x, x))+19*(diff(f3(x), x, x))+22*(diff(f1(x), x))+23*(diff(f1(x), x))+24*(diff(f2(x), x, x))+25*f2(x)+26*f2(x)+27*f3(x)+29*f3(x) = 0, 2*(diff(f1(x), x, x))+3*(diff(f2(x), x, x, x))+4*(diff(f2(x), x))+6*(diff(f3(x), x))+7*f1(x)+(diff(f3(x), x, x))*(diff(f3(x), x))+(diff(f3(x), x))*f3(x)+(diff(f3(x), x))*f3(x) = 0, f1(0) = 0, f1(1) = 0, f2(0) = 0, f2(1) = 0, f3(0) = 0, f3(1) = 0, ((D@@1)(f2))(0) = 0, ((D@@1)(f2))(1) = 0, ((D@@1)(f3))(0) = 0, ((D@@1)(f3))(1) = 0}; dsol5 := dsolve(dsys3, 'maxmesh' = 500, abserr = .1, numeric, range = 0 .. 1, output = listprocedure)12.mw

We find recent applications of the components applied to the linear momentum, circular equations applied to engineering. Just simply replace the vector or scalar fields to thereby reasoning and use the right button.

 

Momento_Lineal_y_Circular.mw

(in spanish)

Atte.

L.AraujoC.

This question is 99% similiar to an previously posted question, but this one has a little twist(s).

 

http://www.mapleprimes.com/questions/200101-Solving-For-Coefficients-Of-Polynomial-Equations

 

Here is the sample problem. Let's say I have the following equations

 

e1:=(a+b+1)x^2 + (a+1)*x^4 = 0;

e2:=(a-b)*x+ (a^2 - 1)*x^3 = 0;

 

One can immediately tell the system is inconsistent because on x^3, we have a = -1,1 but on x and x^2 we have a = -1/2

This is precisely the problem I am facing, my e1 and e2 will eventually get bigger (bigger as in the order of the polynomial will increase) and I keep facing inconsistencies.

However if I could find a way to code it so that I can ask Maple to solve only up to a certain degree it would be great. This will eliminate any inconsistency

 

For example, using the system I have here, the system is consistent up to order 2 (it will always start from constants and up to a certain power). So I will ask Maple to solve the above system up to order 2.

Here is a pseudocode I have been working on.

 

For i = 1..2 //this might be increased, but it will of course be finite and probably won't go past 10.

For j = 0..N


//N is the degree of polynomial

f[i]:= coeff(e[i],x,j);

end

end

 

//the above generates the equations, below will solve it

 

solve( { f[i], i=1..?} ,{a,b})

 

Note that the pseudocode assumes e[i] are expressions and not equations set to 0 (which is what I have). Is there an "un"unapply on maple?

 

edit1: have to sleep  (late where I am! Will check for responses tomorrow) thank you

I have data file with 6 columns:

X Y Z B1 B2 B3

i.e. 3 coordinates (with some step) and values of B-functions at that 3D point. How to make interpolation of these B-functions to have them in arbitrary (x,y,z) point?

Then I need to solve diff equations like this:

x''(s)+f(...)=0

f(...) depends on x,y,z,x',y',z' and B1,B2,B3. How to write this dsolve(...) construction when we have interpolations inside?

Thanks.

I want to  get   nonlinear equations solutions using 'solve',but i always meet that the program running long long time,i want to stop this 'solve' procedure giving a limit time.how do i.can you help me.thanks a lot.

Hey Guys, 

I was wondering how big an algebriac equation has to be before maple crashes. (i cant think of a better word) . I am trying to derive an epression that involves solving 9 equations that all pretty big. about 16 terms. I am substituting in each equation into the next and I get to the last one and it just says evaluating. I left it up overnight and it was still there evaluating. Any help would be appreciated. 

Hi,

I was trying to find the solution for two theta variables in a couple of simultaneous equations (infact this is an iverse kinematics problem for a two link system pendulum).
The following are the initial inputs/equations to be manipulated:


Then I use the folowing command to rearrange for the theta values which I am after:

which gives me the result:

This is all fine until I give in values for l1, l2, x and y:


results:

I have a RootOf in there with a _Z term poping up here and there. I know that this configuration of the two link mechanism in fact dows have a solution and that these numbers are reasonable. Thus I have three questions:

Why does this happen?
What does the "signum" mean here?
how do I go about getting the nummerical values?

Many thanks,
- pjf

How do i proceed to solve two differential equations?

Two equations two unknowns is easy to solve in polynomial algebraic equations. Example: x+y=5; x-y=3; The solution is x=4; y=1 by adding the equations we arrive at.

The two equations are second order differential equations with two variables say temperature T (x,y) and velocity c(x,y). Assume any simple equation (one dimensional as well i.e. T(x) and c(x) which you can demonstrate with ease, I have not formulated the exact equations and boundary conditions yet for SI Engine simulation.

Thanks for comments, suggestions and answers expected eagerly.

Ramakrishnan

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