Duffing oscillator












0












$begingroup$


I have to draw the phase space of this modification of Duffing oscillator:
begin{align}
dot x &= y,\
dot y &= x - x^3 - ay - (x^2)y quad text{ when } quad a=1 ; text{ and } ;a=5.
end{align}



I know that critical points are $(0, 0)$, $(-1, 0)$, and $(1, 0),$ and I have demonstrated that when $a =1$ I have a spiral the form $(pm1,0)$ and when $a = 5$ not.



Does someone know how to draw it?



Thank you.










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  • $begingroup$
    Improve your question, pls.
    $endgroup$
    – Word Shallow
    Jan 15 at 14:33










  • $begingroup$
    Why did you revert back the edit made by Key Flex?
    $endgroup$
    – BigbearZzz
    Jan 15 at 14:50










  • $begingroup$
    Do you mean draw with a computer program or do a sketch by hand if no computer is available?
    $endgroup$
    – LutzL
    Jan 15 at 16:11
















0












$begingroup$


I have to draw the phase space of this modification of Duffing oscillator:
begin{align}
dot x &= y,\
dot y &= x - x^3 - ay - (x^2)y quad text{ when } quad a=1 ; text{ and } ;a=5.
end{align}



I know that critical points are $(0, 0)$, $(-1, 0)$, and $(1, 0),$ and I have demonstrated that when $a =1$ I have a spiral the form $(pm1,0)$ and when $a = 5$ not.



Does someone know how to draw it?



Thank you.










share|cite|improve this question











$endgroup$












  • $begingroup$
    Improve your question, pls.
    $endgroup$
    – Word Shallow
    Jan 15 at 14:33










  • $begingroup$
    Why did you revert back the edit made by Key Flex?
    $endgroup$
    – BigbearZzz
    Jan 15 at 14:50










  • $begingroup$
    Do you mean draw with a computer program or do a sketch by hand if no computer is available?
    $endgroup$
    – LutzL
    Jan 15 at 16:11














0












0








0





$begingroup$


I have to draw the phase space of this modification of Duffing oscillator:
begin{align}
dot x &= y,\
dot y &= x - x^3 - ay - (x^2)y quad text{ when } quad a=1 ; text{ and } ;a=5.
end{align}



I know that critical points are $(0, 0)$, $(-1, 0)$, and $(1, 0),$ and I have demonstrated that when $a =1$ I have a spiral the form $(pm1,0)$ and when $a = 5$ not.



Does someone know how to draw it?



Thank you.










share|cite|improve this question











$endgroup$




I have to draw the phase space of this modification of Duffing oscillator:
begin{align}
dot x &= y,\
dot y &= x - x^3 - ay - (x^2)y quad text{ when } quad a=1 ; text{ and } ;a=5.
end{align}



I know that critical points are $(0, 0)$, $(-1, 0)$, and $(1, 0),$ and I have demonstrated that when $a =1$ I have a spiral the form $(pm1,0)$ and when $a = 5$ not.



Does someone know how to draw it?



Thank you.







ordinary-differential-equations






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share|cite|improve this question













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share|cite|improve this question








edited Jan 15 at 16:07









LutzL

60k42057




60k42057










asked Jan 15 at 14:30









CastiCasti

61




61












  • $begingroup$
    Improve your question, pls.
    $endgroup$
    – Word Shallow
    Jan 15 at 14:33










  • $begingroup$
    Why did you revert back the edit made by Key Flex?
    $endgroup$
    – BigbearZzz
    Jan 15 at 14:50










  • $begingroup$
    Do you mean draw with a computer program or do a sketch by hand if no computer is available?
    $endgroup$
    – LutzL
    Jan 15 at 16:11


















  • $begingroup$
    Improve your question, pls.
    $endgroup$
    – Word Shallow
    Jan 15 at 14:33










  • $begingroup$
    Why did you revert back the edit made by Key Flex?
    $endgroup$
    – BigbearZzz
    Jan 15 at 14:50










  • $begingroup$
    Do you mean draw with a computer program or do a sketch by hand if no computer is available?
    $endgroup$
    – LutzL
    Jan 15 at 16:11
















$begingroup$
Improve your question, pls.
$endgroup$
– Word Shallow
Jan 15 at 14:33




$begingroup$
Improve your question, pls.
$endgroup$
– Word Shallow
Jan 15 at 14:33












$begingroup$
Why did you revert back the edit made by Key Flex?
$endgroup$
– BigbearZzz
Jan 15 at 14:50




$begingroup$
Why did you revert back the edit made by Key Flex?
$endgroup$
– BigbearZzz
Jan 15 at 14:50












$begingroup$
Do you mean draw with a computer program or do a sketch by hand if no computer is available?
$endgroup$
– LutzL
Jan 15 at 16:11




$begingroup$
Do you mean draw with a computer program or do a sketch by hand if no computer is available?
$endgroup$
– LutzL
Jan 15 at 16:11










1 Answer
1






active

oldest

votes


















0












$begingroup$

This may help you



enter image description here



generated with python:



import numpy as  np
import matplotlib.pyplot as plt

xmin, xmax = -2.0, 2.0
ymin, ymax = -1.0, 1.0

x, y = np.meshgrid(np.linspace(xmin, xmax, 30, endpoint = True), np.linspace(ymin, ymax, 30, endpoint = True))

a = 1
u = y
v = x - x**3 - a * y - x**2 * y


plt.streamplot(x, y, u, v)
plt.show()





share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you very much, your answer has been very helpful.
    $endgroup$
    – Casti
    Jan 15 at 17:16












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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0












$begingroup$

This may help you



enter image description here



generated with python:



import numpy as  np
import matplotlib.pyplot as plt

xmin, xmax = -2.0, 2.0
ymin, ymax = -1.0, 1.0

x, y = np.meshgrid(np.linspace(xmin, xmax, 30, endpoint = True), np.linspace(ymin, ymax, 30, endpoint = True))

a = 1
u = y
v = x - x**3 - a * y - x**2 * y


plt.streamplot(x, y, u, v)
plt.show()





share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you very much, your answer has been very helpful.
    $endgroup$
    – Casti
    Jan 15 at 17:16
















0












$begingroup$

This may help you



enter image description here



generated with python:



import numpy as  np
import matplotlib.pyplot as plt

xmin, xmax = -2.0, 2.0
ymin, ymax = -1.0, 1.0

x, y = np.meshgrid(np.linspace(xmin, xmax, 30, endpoint = True), np.linspace(ymin, ymax, 30, endpoint = True))

a = 1
u = y
v = x - x**3 - a * y - x**2 * y


plt.streamplot(x, y, u, v)
plt.show()





share|cite|improve this answer









$endgroup$













  • $begingroup$
    Thank you very much, your answer has been very helpful.
    $endgroup$
    – Casti
    Jan 15 at 17:16














0












0








0





$begingroup$

This may help you



enter image description here



generated with python:



import numpy as  np
import matplotlib.pyplot as plt

xmin, xmax = -2.0, 2.0
ymin, ymax = -1.0, 1.0

x, y = np.meshgrid(np.linspace(xmin, xmax, 30, endpoint = True), np.linspace(ymin, ymax, 30, endpoint = True))

a = 1
u = y
v = x - x**3 - a * y - x**2 * y


plt.streamplot(x, y, u, v)
plt.show()





share|cite|improve this answer









$endgroup$



This may help you



enter image description here



generated with python:



import numpy as  np
import matplotlib.pyplot as plt

xmin, xmax = -2.0, 2.0
ymin, ymax = -1.0, 1.0

x, y = np.meshgrid(np.linspace(xmin, xmax, 30, endpoint = True), np.linspace(ymin, ymax, 30, endpoint = True))

a = 1
u = y
v = x - x**3 - a * y - x**2 * y


plt.streamplot(x, y, u, v)
plt.show()






share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Jan 15 at 15:11









caveraccaverac

14.8k31130




14.8k31130












  • $begingroup$
    Thank you very much, your answer has been very helpful.
    $endgroup$
    – Casti
    Jan 15 at 17:16


















  • $begingroup$
    Thank you very much, your answer has been very helpful.
    $endgroup$
    – Casti
    Jan 15 at 17:16
















$begingroup$
Thank you very much, your answer has been very helpful.
$endgroup$
– Casti
Jan 15 at 17:16




$begingroup$
Thank you very much, your answer has been very helpful.
$endgroup$
– Casti
Jan 15 at 17:16


















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