## Problem with system of equations...

Hi

Anyone could help me in solving the following system of equations to get constants C1, C2, C3 and C4. MALPE give me this "soution may have been lost".  The MAPLE sheet is also attached.

 > restart:
 > Eq1:=simplify(C3*exp(-(1/4)*(C2*(x^2-2*0)+sqrt(C2*(x^2-2*0)^2+4*M*(x^2-2*0)*w1*(x^2-2*0)))/w1)+C4*exp((1/4)*(-C2*(x^2-2*0)+sqrt(C2*(x^2-2*0)^2+4*M*(x^2-2*0)*w1*(x^2-2*0)))/w1)-U) = 0;
 (1)
 > Eq2:=simplify(exp(-(1/4)*(C2+sqrt(C2^2+4*M*w1))*(x^2-2*0)/w1)*C3*x+exp((1/4)*(-C2+sqrt(C2^2+4*M*w1))*(x^2-2*0)/w1)*C4*x+C2-V-z) = 0;
 (2)
 > Eq3:=simplify((-2*w2*w5*ln(C3*exp(-(1/2)*sqrt(w2*w4*(w2*w4+w3*w6))*C2*(x^2-2*0)/(w2*w4*w5))-C4)*sqrt(w2*w4*(w2*w4+w3*w6))+w2*w5*(-w2*w4+sqrt(w2*w4*(w2*w4+w3*w6)))*ln(exp(-(1/2)*sqrt(w2*w4*(w2*w4+w3*w6))*C2*(x^2-2*0)/(w2*w4*w5)))+C1*w3*w6*sqrt(w2*w4*(w2*w4+w3*w6)))/(sqrt(w2*w4*(w2*w4+w3*w6))*w3*w6)-1)= 0;
 (3)
 > Eq4:= simplify((-C2*x^2*w2*w4-.50*C2*x^2*w3*w6+sqrt(w2*w4*(w2*w4+w3*w6))*C2*x^2+2.*w2*w4*w5*ln(w3^4*w6^2*(C3^2*exp(-1.0*sqrt(w2*w4*(w2*w4+w3*w6))*C2*x^2/(w2*w4*w5))-2*C3*exp(-.5*sqrt(w2^2*w4^2+w2*w3*w4*w6)*C2*x^2/(w2*w4*w5))*C4+C4^2)/(w2*w4*(w2*w4+w3*w6)*C2^2))-5.544000000*w2*w4*w5-w3^2*w6)/(w3^2*w6)) = 0;
 (4)
 > solve({Eq1, Eq2, Eq3,Eq4}, {C1, C2, C3,C4});
 >

## solveing 4 set equations...

hi guys, i have a complicated 4 set equations and i want to solve it,

one way is to find a solution for an equation and check it manually in other equations but i am looking for better method

eqq.mw

thanks

## Finding unknowns from a set of equations...

Hello everybody.

In the attached file, you find 6 equations. All of these parameters are known except "pd" and "qd". How can I find these two unknowns from 6 equations??? It should be pointed out that, "pd" and "qd" must contain "ud", "vd","wd" and "rd".

D.mw

## dsolve with unknown parameter...

hi.I want to dsolve set of nonlinear equations with one unknown parameter ...is this possible with dsolve rule.in matlab this possible with bvp4c rule..please help me for this problem.if we should another rule please attached file reform.Thanks alot12.mw

## Solving with Enumeration...

I need to solve a set of equations but changing a constant each time.

For example, x+by=0, bx-y=10 where b=10,20.

I don't want to put it in a loop because, in loop, the equations are solved repeatedly. I want Maple to solve it only once and substitute b values automatically since I want to solve big set of equations faster.

Is there any option in Maple to do so with a single command

## Expressions from Matlab to equations in Maple...

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 ?

## spiral formation...

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

## RSCR spatial mechanism

by:

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

## solutions may have been lost...

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

 >
 (1)
 >
 (2)
 >
 >

thanks

## Error, (in dsolve/numeric/bvp/convertsys) unable t...

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

## Momentum Linear and Circular with Maple.

Maple 2015

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.

## Solving for coefficients in polynomial....

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

## dsolve with interpolating functions...

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.