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Hi guys,

im trying to solve the linear equation system:

mysol := solve({J*a = m*l*(-c*ct^2*sf-c*sf*st^2+cf*d*st^2+d*sf*st^2)+m*g*l*st, cx*ux = cMx*xd+M*c+m*l*(-cp*pd^2*st-cp*st*td^2-2*ct*pd*sp*td+a*cp*ct-b*sp*st), cy*uy = cMy*yd+M*d+m*l*(2*cp*ct*pd*td-pd^2*sp*st-sp*st*td^2+a*ct*sp+b*cp*st), (-l^2*m*st^2+J)*b = -ml(c*cf*ct+ct*d*sf)}, {a, b, c, d}) :

Then, assigning the solutions:

assign(mysol):

Then, eliminating the RootOf's for variable a:

a_explicit := allvalues(a):

Unfortunately, a_explicit still contains RootOf's. How can I avoid this?

Thanks,

Martin

 

Up to Maple Help, the relatively new command SolveTools[Engine] with the
allsolutions option returns parameterized solutions for non-algebraic equations which may have infinitely many solutions. The question arises: how to extract these?
For example,
sol := SolveTools:-Engine({tan(x) = x}, [x], allsolutions);
[{x = RootOf(-tan(_Z)+_Z)}]
I want to extract the third positive solution (by its value), trying
evalf(allvalues(sol));
[{x = -4.493409458}], [{x = 0.}]
Is it possible at all?

Hello,

Assume a periodic signal that is the sum of four sinusoidal signals, all with different frequency and phase. The fundamental frequency has phase=0, so at t=0 its value is 0 (a zero crossing point). I need to find the influence of the other frequency components on the zero crossing point in [seconds] as an analytical expression. I made the Maple script below to find out, but get a RootOf result. How can I solve this?

Thanks for your help!

restart

p := a*sin(omega[P]*t):

q := b*sin(t*omega[Q]+phi[Q]):

r := c*sin(t*omega[R]+phi[R]):

s := d*sin(t*omega[S]+phi[S]):

z := p+q+r+s

a*sin(omega[P]*t)+b*sin(t*omega[Q]+phi[Q])+c*sin(t*omega[R]+phi[R])+d*sin(t*omega[S]+phi[S])

(1)

solve(z, t)

RootOf(sin(_Z)*a+b*sin((_Z*omega[Q]+omega[P]*phi[Q])/omega[P])+c*sin((_Z*omega[R]+omega[P]*phi[R])/omega[P])+d*sin((_Z*omega[S]+omega[P]*phi[S])/omega[P]))/omega[P]

(2)

``


Download 20131130_Zero_crossi.mw

I want to invlaplace the following complex expression that I call PQ.

>PQ:=(cosh((1/2)*eta*sqrt(C3^2+4*C1*s))*sqrt(C3^2+4*C1*s)+sinh((1/2)*eta*sqrt(C3^2+4*C1*s))*C3)*(cosh((1/2)*eta*C3)-sinh((1/2)*eta*C3))*(-cosh(C4)-sinh(C4)+s)/(s^2*(-sinh((1/2)*C3)+cosh((1/2)*C3))*(sinh((1/2)*sqrt(C3^2+4*C1*s))*C3+sqrt(C3^2+4*C1*s)*cosh((1/2)*sqrt(C3^2+4*C1*s))))

where C1 C3 C4 eta are constant .

Then I do like this

>invlaplace(PQ)

But I got

Hi,

How do I get ride of these Rootof?

I tried simplify,evala,value,Simplify and ect. Didnt really find anything useful.

Download rootof.mw

 

I dont care which root they actually take, all I want is one of the roots. So I can then use subs for substitution.

Casper

I would like to plot the following expression that I call W

>W:=tau*exp(C4)/C1-exp(C4)*(exp(C3-C3*eta)/C3^2-exp(C3)/C3^2+tau/C1+eta/C3)+exp(C4-C3*eta/2)*Sum(16*beta[m]*sin(beta[m]*eta/2)*exp(-(beta[m]*beta[m]+C3^2)*tau/(4*C1))/((beta[m]*beta[m]+C3^2)*( beta[m]*beta[m]-C3^2)^2),m=1..n)

Where C1, C3, C4 are constant, and  beta[m]satisfies the relationship  

C3*sin (beta/2) =beta*cos (beta/2)

I want to plot the W-eta curve and W-tau curve (eta at [0, 1...

I would like to solve the following equation that I call equ?

> equ: = tanh(s)=C3*s

To do this I use the code “solve” to solve it. C3 is constant.

> sol: =solve (equ,s)

RootOf(_Z*C3*(exp(_Z))^2+_Z*C3-(exp(_Z))^2+1)

I then get the RootOf expression. How to get its mathematical expressions? I am really interested in getting it.

Please help me in anyway you can as I am completely stuck

I would like to integrate the following expression that I call res

>res:= subs([S1 = C3-sqrt(C3^2+4*C1*s), S2 = C3+sqrt(C3^2+4*C1*s)], exp(s*t)*(S1*(sinh((1/2)*S1)-cosh((1/2)*S1))*(sinh((1/2)*S2*eta)-cosh((1/2)*S2*eta))-S2*(sinh((1/2)*S2)-cosh((1/2)*S2))*(sinh((1/2...

Hi,

I'm dealing with an iterated function (logistic map) where f(x)=s*x*(1-x) where the s is a general parameter between 1 and 4 inclusive, and it's fourth return map, or f(f(f(f(x)))) or f^[4](x).

h:x->f(f(f(f(x))))

What I'm trying to do hinges on evaluating this:

solve(h(x)=x,x);

a

Hello guys ,

 

i have a complicated function , i found its roots but when i evaluate function by its roots , the result is not zero !!!

 

thank you for your helpWork.mw

need to find the explicit root of u where k,b are  positive constants:

eq5:=u->-3*b*k*u^2-3*b*k^2*u^4-k^3*u^6*b+k*u+5*k^2*u^3-b;

sol:=(solve(eq5(u),u)): S:=array([],1..3): S[1]:=((sol[1]));S[2]:=sol[2]:S[3]:=sol[3]:S[4]:=sol[4]:S[5]:=sol[5]:S[6]:=sol[6]:

and choose the positive real root and substitute it in another equation.

and then plot k against b as:

i'm trying to solve this parametric parametequation(a1,a2 & l are parameters and n is my variable): 

a2*(l^(2*n)-1)-2*(a1+n*a2)*(l^n)*log(l)=0

when i try to solve this parametric equation, maple return a RootOf term and when i try to see the values of this RootOf by Allvalues, again return a RootOf, but when i replace the parameters by numbers(like a1=400, a2=25 & l=3.2), maple return a unique n. 

Dear all,

I’m a beginner in Maple and I have problem in understanding the RootOf

my equations are shown below:

 

M1alone := (1/2)*hs*fm*sigma*mu/(Ps*sqrt(sqrt(M1/h0)/Ps+ts))-As*h0*mu^2/M1 = (1/2)*hs*mu^2/Ps-(1/2)*hs*mu:

> M1sol := isolate(M1alone, M1);

M1 = Ps^2*(-ts+RootOf((-hs*mu*Ps+hs*Ps^2)*_Z^5+hs*fm*sigma*_Z^4*Ps+(-2*hs*Ps^2*ts+2*hs*mu*ts*Ps)*_Z^3-2*hs*fm*sigma*ts*Ps*_Z^2+(hs*Ps^2*ts^2-2*As*mu-hs*mu*ts^2*Ps...

In the following script, I am trying to understand why evala returns an error. It returns

                Error, (in evala/Reduce/nf/indep) invalid arguments to coeffs

in a couple of places. I tried, and I can get around the errors by doing it a complex way, but it seems like I'm just not using evala correctly. Perhaps someone can comment? I'd very much appreciate it.

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