Math-dashti

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i have a system but i don't know how i can plot chaotic or is need time for ploting or not ?

Regarding to this equation i want to do the same as paper did, but i am not sure how i can determine the both  point in plot and how thus point show effect of system of equation and  how find jacobian in the two different point  i think he find it in general but i think we have to find it for each one  of equalibriom point  or we just find in general .
thus plot also are emazing did he use special code in matlab or mathematica? there is some app for plot thus kind of phase portrait but they not like this this is must have a special code for plotting in matlab or mathematica

restart

with(PDEtools)

undeclare(prime, quiet)

with(LinearAlgebra)

declare(u(x, t), quiet); declare(U(xi), quiet); declare(V(xi), quiet)

NULL

DU := V

V

(1)

DV := U^2*beta/(delta*k^2)+(alpha*w/(delta*k^3)+1/(delta*k^2)-w^2/(delta*k^4))*U

U^2*beta/(delta*k^2)+(alpha*w/(delta*k^3)+1/(delta*k^2)-w^2/(delta*k^4))*U

(2)

var := U, V

U, V

(3)

J := Student:-MultivariateCalculus:-Jacobian([DU, DV], [var], 'output' = 'matrix')

Matrix(%id = 36893490902008029780)

(4)

Eigenvalues(J, implicit, output = 'list')

[RootOf(_Z^2*delta*k^4-2*U*beta*k^2-alpha*k*w-k^2+w^2, index = 1), RootOf(_Z^2*delta*k^4-2*U*beta*k^2-alpha*k*w-k^2+w^2, index = 2)]

(5)

Eigenvalues(J)

Vector[column](%id = 36893490902007993756)

(6)

NULL

NULL

DU1 := V

V

(7)

V = solve(DU1, V)

V = 0

(8)

DV1 := U^2*F[2]+U*F[1]

U^2*F[2]+U*F[1]

(9)

U = solve(DV1, U)

U = (0, -F[1]/F[2])

(10)

so*we*have*three*equalibriom*point*(0, 0)

so*we*have*three*equalibriom*point*(0, 0)

(11)

J1 := Student:-MultivariateCalculus:-Jacobian([DU1, DV1], [var], 'output' = 'matrix')

Matrix(%id = 36893490902007256836)

(12)

Eigenvalues(J1, implicit, output = 'list')

[RootOf(-2*U*F[2]+_Z^2-F[1], index = 1), RootOf(-2*U*F[2]+_Z^2-F[1], index = 2)]

(13)

Eigenvalues(J1)

Vector[column](%id = 36893490901938203092)

(14)
 

NULL

Download bi-1.mw

in thus example all of them are write in shape of matrix but all of them are linear differential equation which have critical point zero ,i want to plot thus example and decided the kind of critical point by eagenvalue and by eagenvector i can find the trajectory how i can plot by matrix of each example and show that that critical point is which type as mention in picture?

system-phase-examples.mw

i want plot like that but i can't  and there is anyway for finding the equalibriom point of system? 

restart

with(PDEtools)

with(LinearAlgebra)

with(DEtools)

with(DynamicSystems)

sys := {diff(x(t), t) = 2*x(t)+3*y(t), diff(y(t), t) = 2*x(t)+y(t)}

{diff(x(t), t) = 2*x(t)+3*y(t), diff(y(t), t) = 2*x(t)+y(t)}

(1)

fns := {x(t), y(t)}

{x(t), y(t)}

(2)

sol := dsolve(sys, fns)

{x(t) = c__1*exp(4*t)+c__2*exp(-t), y(t) = (2/3)*c__1*exp(4*t)-c__2*exp(-t)}

(3)

ode := [diff(x(t), t) = 2*x(t)+3*y(t), diff(y(t), t) = 2*x(t)+y(t)]; S := dsolve(ode)

[diff(x(t), t) = 2*x(t)+3*y(t), diff(y(t), t) = 2*x(t)+y(t)]

 

{x(t) = c__1*exp(4*t)+c__2*exp(-t), y(t) = (2/3)*c__1*exp(4*t)-c__2*exp(-t)}

(4)

Student:-ODEs:-ODESteps(ode, {x(t), y(t)})

"[[,,"Let's solve"],[,,[(ⅆ)/(ⅆt) x(t)=2 x(t)+3 y(t),(ⅆ)/(ⅆt) y(t)=2 x(t)+y(t)]],["•",,"Define vector"],[,,x(t)=[?]],["•",,"Convert system into a vector equation"],[,,(ⅆ)/(ⅆt) x(t)=[?]*x(t)+[?]],["•",,"System to solve"],[,,(ⅆ)/(ⅆt) x(t)=[?]*x(t)],["•",,"Define the coefficient matrix"],[,,A=[?]],["•",,"Rewrite the system as"],[,,(ⅆ)/(ⅆt) x(t)=A*x(t)],["•",,"To solve the system, find the eigenvalues and eigenvectors of" A],["•",,"Eigenpairs of" A],[,,[[-1,[?]],[4,[?]]]],["•",,"Consider eigenpair"],[,,[-1,RTABLE(18446744074191517278,MATRIX([[-1], [1]]),Vector[column])]],["•",,"Solution to homogeneous system from eigenpair"],[,,(x)[1]=[]],["•",,"Consider eigenpair"],[,,[4,RTABLE(18446744074192645174,MATRIX([[3/2], [1]]),Vector[column])]],["•",,"Solution to homogeneous system from eigenpair"],[,,(x)[2]=[]],["•",,"General solution to the system of ODEs"],[,,x=`c__1` (x)[1]+`c__2` (x)[2]],["•",,"Substitute solutions into the general solution"],[,,x=[]+[]],["•",,"Substitute in vector of dependent variables"],[,,[?]=[?]],["•",,"Solution to the system of ODEs"],[,,{x(t)=-`c__1` (e)^(-t)+(3 `c__2` (e)^(4 t))/2,y(t)=`c__1` (e)^(-t)+`c__2` (e)^(4 t)}]]"

(5)
 

NULL

Download Plot-1.mw

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