What exactly is a defective nodal source

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I attain repeated root eigenvalue of $-1$ with eigenvector $beginpmatrix2\1endpmatrix$



However, I'm uncertain if the general solution would be $c_1cdot e^-tbeginpmatrix2\1endpmatrix$ alone, or would it be $c_1cdot e^-tbeginpmatrix2\1endpmatrix + c_2cdot tcdot e^-tbeginpmatrix2\1endpmatrix$.



Likewise, when I plot the phase portriat in software, I receive an alert claiming that the phase protriat is a defective nodal source. What is that exactly?







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  • Your second attempt should be the right hence a general solution never consists only of one term. But I guess you need to rework the second eigenvector.
    – mrtaurho
    Jul 22 at 15:15











  • so I got my general solution as e^t(c1*(2;1)+c2(t(2;1)+(-4,0)). However, how can I solve this IVP with just one initial conditions and two arbitrary constants?
    – SleepApnea
    Jul 22 at 15:24










  • so I finalized my general solution to be e^t(c1(2,1)+c2(t(2,1)+(-4,0)) However, I do not understand how to solve the IVP with two constants unknown, and only one condition.
    – SleepApnea
    Jul 22 at 15:27










  • Since you are working on a system of differential equations there is no problem in calculating the constants. Just set the general solution equal to the IVP and split it up in two equations : now you got a linear system of two equations and two variables.
    – mrtaurho
    Jul 22 at 15:33










  • is my general solution correct to add the additional (-4,0) at the tail end of the problem?
    – SleepApnea
    Jul 22 at 15:35














up vote
0
down vote

favorite












enter image description here



I attain repeated root eigenvalue of $-1$ with eigenvector $beginpmatrix2\1endpmatrix$



However, I'm uncertain if the general solution would be $c_1cdot e^-tbeginpmatrix2\1endpmatrix$ alone, or would it be $c_1cdot e^-tbeginpmatrix2\1endpmatrix + c_2cdot tcdot e^-tbeginpmatrix2\1endpmatrix$.



Likewise, when I plot the phase portriat in software, I receive an alert claiming that the phase protriat is a defective nodal source. What is that exactly?







share|cite|improve this question





















  • Your second attempt should be the right hence a general solution never consists only of one term. But I guess you need to rework the second eigenvector.
    – mrtaurho
    Jul 22 at 15:15











  • so I got my general solution as e^t(c1*(2;1)+c2(t(2;1)+(-4,0)). However, how can I solve this IVP with just one initial conditions and two arbitrary constants?
    – SleepApnea
    Jul 22 at 15:24










  • so I finalized my general solution to be e^t(c1(2,1)+c2(t(2,1)+(-4,0)) However, I do not understand how to solve the IVP with two constants unknown, and only one condition.
    – SleepApnea
    Jul 22 at 15:27










  • Since you are working on a system of differential equations there is no problem in calculating the constants. Just set the general solution equal to the IVP and split it up in two equations : now you got a linear system of two equations and two variables.
    – mrtaurho
    Jul 22 at 15:33










  • is my general solution correct to add the additional (-4,0) at the tail end of the problem?
    – SleepApnea
    Jul 22 at 15:35












up vote
0
down vote

favorite









up vote
0
down vote

favorite











enter image description here



I attain repeated root eigenvalue of $-1$ with eigenvector $beginpmatrix2\1endpmatrix$



However, I'm uncertain if the general solution would be $c_1cdot e^-tbeginpmatrix2\1endpmatrix$ alone, or would it be $c_1cdot e^-tbeginpmatrix2\1endpmatrix + c_2cdot tcdot e^-tbeginpmatrix2\1endpmatrix$.



Likewise, when I plot the phase portriat in software, I receive an alert claiming that the phase protriat is a defective nodal source. What is that exactly?







share|cite|improve this question













enter image description here



I attain repeated root eigenvalue of $-1$ with eigenvector $beginpmatrix2\1endpmatrix$



However, I'm uncertain if the general solution would be $c_1cdot e^-tbeginpmatrix2\1endpmatrix$ alone, or would it be $c_1cdot e^-tbeginpmatrix2\1endpmatrix + c_2cdot tcdot e^-tbeginpmatrix2\1endpmatrix$.



Likewise, when I plot the phase portriat in software, I receive an alert claiming that the phase protriat is a defective nodal source. What is that exactly?









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Jul 22 at 15:12









mrtaurho

740219




740219









asked Jul 22 at 15:00









SleepApnea

426




426











  • Your second attempt should be the right hence a general solution never consists only of one term. But I guess you need to rework the second eigenvector.
    – mrtaurho
    Jul 22 at 15:15











  • so I got my general solution as e^t(c1*(2;1)+c2(t(2;1)+(-4,0)). However, how can I solve this IVP with just one initial conditions and two arbitrary constants?
    – SleepApnea
    Jul 22 at 15:24










  • so I finalized my general solution to be e^t(c1(2,1)+c2(t(2,1)+(-4,0)) However, I do not understand how to solve the IVP with two constants unknown, and only one condition.
    – SleepApnea
    Jul 22 at 15:27










  • Since you are working on a system of differential equations there is no problem in calculating the constants. Just set the general solution equal to the IVP and split it up in two equations : now you got a linear system of two equations and two variables.
    – mrtaurho
    Jul 22 at 15:33










  • is my general solution correct to add the additional (-4,0) at the tail end of the problem?
    – SleepApnea
    Jul 22 at 15:35
















  • Your second attempt should be the right hence a general solution never consists only of one term. But I guess you need to rework the second eigenvector.
    – mrtaurho
    Jul 22 at 15:15











  • so I got my general solution as e^t(c1*(2;1)+c2(t(2;1)+(-4,0)). However, how can I solve this IVP with just one initial conditions and two arbitrary constants?
    – SleepApnea
    Jul 22 at 15:24










  • so I finalized my general solution to be e^t(c1(2,1)+c2(t(2,1)+(-4,0)) However, I do not understand how to solve the IVP with two constants unknown, and only one condition.
    – SleepApnea
    Jul 22 at 15:27










  • Since you are working on a system of differential equations there is no problem in calculating the constants. Just set the general solution equal to the IVP and split it up in two equations : now you got a linear system of two equations and two variables.
    – mrtaurho
    Jul 22 at 15:33










  • is my general solution correct to add the additional (-4,0) at the tail end of the problem?
    – SleepApnea
    Jul 22 at 15:35















Your second attempt should be the right hence a general solution never consists only of one term. But I guess you need to rework the second eigenvector.
– mrtaurho
Jul 22 at 15:15





Your second attempt should be the right hence a general solution never consists only of one term. But I guess you need to rework the second eigenvector.
– mrtaurho
Jul 22 at 15:15













so I got my general solution as e^t(c1*(2;1)+c2(t(2;1)+(-4,0)). However, how can I solve this IVP with just one initial conditions and two arbitrary constants?
– SleepApnea
Jul 22 at 15:24




so I got my general solution as e^t(c1*(2;1)+c2(t(2;1)+(-4,0)). However, how can I solve this IVP with just one initial conditions and two arbitrary constants?
– SleepApnea
Jul 22 at 15:24












so I finalized my general solution to be e^t(c1(2,1)+c2(t(2,1)+(-4,0)) However, I do not understand how to solve the IVP with two constants unknown, and only one condition.
– SleepApnea
Jul 22 at 15:27




so I finalized my general solution to be e^t(c1(2,1)+c2(t(2,1)+(-4,0)) However, I do not understand how to solve the IVP with two constants unknown, and only one condition.
– SleepApnea
Jul 22 at 15:27












Since you are working on a system of differential equations there is no problem in calculating the constants. Just set the general solution equal to the IVP and split it up in two equations : now you got a linear system of two equations and two variables.
– mrtaurho
Jul 22 at 15:33




Since you are working on a system of differential equations there is no problem in calculating the constants. Just set the general solution equal to the IVP and split it up in two equations : now you got a linear system of two equations and two variables.
– mrtaurho
Jul 22 at 15:33












is my general solution correct to add the additional (-4,0) at the tail end of the problem?
– SleepApnea
Jul 22 at 15:35




is my general solution correct to add the additional (-4,0) at the tail end of the problem?
– SleepApnea
Jul 22 at 15:35










1 Answer
1






active

oldest

votes

















up vote
0
down vote



accepted










In the case of repeated real roots you need to calculate a different second eigenvector which satisfies the equation



$$beginpmatrixa-lambda & b\c & d-lambdaendpmatrixbeginpmatrixrho_1\rho_2endpmatrix~=~beginpmatrixeta_1\eta_2endpmatrix$$



where $beginpmatrixeta_1\eta_2endpmatrix$ is the first eigenvector and $lambda$ is the eigenvalue of the matrix. From there on you can conclude to the general solution of the form



$$vecx~=~c_1cdot e^lambda tveceta+c_2(tcdot e^lambda tveceta+e^lambda tvecrho)$$




The eigenvalues of the given systems are the repeated real roots $lambda_1,2=-1$. From there one you get the first eigenvector $beginpmatrix2\1endpmatrix$ as you already did. Now just calculate the second eigenvector and you are done.






share|cite|improve this answer























  • based on my general solution: e^t(c1(2,1)+c2(t(2,1)+(-4,0)). Then if we use the IVP and plug in t = 0, I get (1,1) = c1(2,1) + c2(-4,0). I don't really understand how to isolate C1 and C2.
    – SleepApnea
    Jul 22 at 15:36











  • Just cosider it as a system of the two equations $1=c_1-4c_2$ and $1=-4c_1$
    – mrtaurho
    Jul 22 at 15:44










  • Based on the phase portrait of this particular case, can I argue that when t either moves to infinity or negative infinity, the phase portrait is moving tangentially inwards towards the origin.
    – SleepApnea
    Jul 22 at 16:54










  • Could you maybe link the phase potrait somewhere?
    – mrtaurho
    Jul 22 at 16:58










  • ibb.co/cDCyby This is the phase portrait.
    – SleepApnea
    Jul 22 at 17:30











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
0
down vote



accepted










In the case of repeated real roots you need to calculate a different second eigenvector which satisfies the equation



$$beginpmatrixa-lambda & b\c & d-lambdaendpmatrixbeginpmatrixrho_1\rho_2endpmatrix~=~beginpmatrixeta_1\eta_2endpmatrix$$



where $beginpmatrixeta_1\eta_2endpmatrix$ is the first eigenvector and $lambda$ is the eigenvalue of the matrix. From there on you can conclude to the general solution of the form



$$vecx~=~c_1cdot e^lambda tveceta+c_2(tcdot e^lambda tveceta+e^lambda tvecrho)$$




The eigenvalues of the given systems are the repeated real roots $lambda_1,2=-1$. From there one you get the first eigenvector $beginpmatrix2\1endpmatrix$ as you already did. Now just calculate the second eigenvector and you are done.






share|cite|improve this answer























  • based on my general solution: e^t(c1(2,1)+c2(t(2,1)+(-4,0)). Then if we use the IVP and plug in t = 0, I get (1,1) = c1(2,1) + c2(-4,0). I don't really understand how to isolate C1 and C2.
    – SleepApnea
    Jul 22 at 15:36











  • Just cosider it as a system of the two equations $1=c_1-4c_2$ and $1=-4c_1$
    – mrtaurho
    Jul 22 at 15:44










  • Based on the phase portrait of this particular case, can I argue that when t either moves to infinity or negative infinity, the phase portrait is moving tangentially inwards towards the origin.
    – SleepApnea
    Jul 22 at 16:54










  • Could you maybe link the phase potrait somewhere?
    – mrtaurho
    Jul 22 at 16:58










  • ibb.co/cDCyby This is the phase portrait.
    – SleepApnea
    Jul 22 at 17:30















up vote
0
down vote



accepted










In the case of repeated real roots you need to calculate a different second eigenvector which satisfies the equation



$$beginpmatrixa-lambda & b\c & d-lambdaendpmatrixbeginpmatrixrho_1\rho_2endpmatrix~=~beginpmatrixeta_1\eta_2endpmatrix$$



where $beginpmatrixeta_1\eta_2endpmatrix$ is the first eigenvector and $lambda$ is the eigenvalue of the matrix. From there on you can conclude to the general solution of the form



$$vecx~=~c_1cdot e^lambda tveceta+c_2(tcdot e^lambda tveceta+e^lambda tvecrho)$$




The eigenvalues of the given systems are the repeated real roots $lambda_1,2=-1$. From there one you get the first eigenvector $beginpmatrix2\1endpmatrix$ as you already did. Now just calculate the second eigenvector and you are done.






share|cite|improve this answer























  • based on my general solution: e^t(c1(2,1)+c2(t(2,1)+(-4,0)). Then if we use the IVP and plug in t = 0, I get (1,1) = c1(2,1) + c2(-4,0). I don't really understand how to isolate C1 and C2.
    – SleepApnea
    Jul 22 at 15:36











  • Just cosider it as a system of the two equations $1=c_1-4c_2$ and $1=-4c_1$
    – mrtaurho
    Jul 22 at 15:44










  • Based on the phase portrait of this particular case, can I argue that when t either moves to infinity or negative infinity, the phase portrait is moving tangentially inwards towards the origin.
    – SleepApnea
    Jul 22 at 16:54










  • Could you maybe link the phase potrait somewhere?
    – mrtaurho
    Jul 22 at 16:58










  • ibb.co/cDCyby This is the phase portrait.
    – SleepApnea
    Jul 22 at 17:30













up vote
0
down vote



accepted







up vote
0
down vote



accepted






In the case of repeated real roots you need to calculate a different second eigenvector which satisfies the equation



$$beginpmatrixa-lambda & b\c & d-lambdaendpmatrixbeginpmatrixrho_1\rho_2endpmatrix~=~beginpmatrixeta_1\eta_2endpmatrix$$



where $beginpmatrixeta_1\eta_2endpmatrix$ is the first eigenvector and $lambda$ is the eigenvalue of the matrix. From there on you can conclude to the general solution of the form



$$vecx~=~c_1cdot e^lambda tveceta+c_2(tcdot e^lambda tveceta+e^lambda tvecrho)$$




The eigenvalues of the given systems are the repeated real roots $lambda_1,2=-1$. From there one you get the first eigenvector $beginpmatrix2\1endpmatrix$ as you already did. Now just calculate the second eigenvector and you are done.






share|cite|improve this answer















In the case of repeated real roots you need to calculate a different second eigenvector which satisfies the equation



$$beginpmatrixa-lambda & b\c & d-lambdaendpmatrixbeginpmatrixrho_1\rho_2endpmatrix~=~beginpmatrixeta_1\eta_2endpmatrix$$



where $beginpmatrixeta_1\eta_2endpmatrix$ is the first eigenvector and $lambda$ is the eigenvalue of the matrix. From there on you can conclude to the general solution of the form



$$vecx~=~c_1cdot e^lambda tveceta+c_2(tcdot e^lambda tveceta+e^lambda tvecrho)$$




The eigenvalues of the given systems are the repeated real roots $lambda_1,2=-1$. From there one you get the first eigenvector $beginpmatrix2\1endpmatrix$ as you already did. Now just calculate the second eigenvector and you are done.







share|cite|improve this answer















share|cite|improve this answer



share|cite|improve this answer








edited Jul 22 at 15:49


























answered Jul 22 at 15:30









mrtaurho

740219




740219











  • based on my general solution: e^t(c1(2,1)+c2(t(2,1)+(-4,0)). Then if we use the IVP and plug in t = 0, I get (1,1) = c1(2,1) + c2(-4,0). I don't really understand how to isolate C1 and C2.
    – SleepApnea
    Jul 22 at 15:36











  • Just cosider it as a system of the two equations $1=c_1-4c_2$ and $1=-4c_1$
    – mrtaurho
    Jul 22 at 15:44










  • Based on the phase portrait of this particular case, can I argue that when t either moves to infinity or negative infinity, the phase portrait is moving tangentially inwards towards the origin.
    – SleepApnea
    Jul 22 at 16:54










  • Could you maybe link the phase potrait somewhere?
    – mrtaurho
    Jul 22 at 16:58










  • ibb.co/cDCyby This is the phase portrait.
    – SleepApnea
    Jul 22 at 17:30

















  • based on my general solution: e^t(c1(2,1)+c2(t(2,1)+(-4,0)). Then if we use the IVP and plug in t = 0, I get (1,1) = c1(2,1) + c2(-4,0). I don't really understand how to isolate C1 and C2.
    – SleepApnea
    Jul 22 at 15:36











  • Just cosider it as a system of the two equations $1=c_1-4c_2$ and $1=-4c_1$
    – mrtaurho
    Jul 22 at 15:44










  • Based on the phase portrait of this particular case, can I argue that when t either moves to infinity or negative infinity, the phase portrait is moving tangentially inwards towards the origin.
    – SleepApnea
    Jul 22 at 16:54










  • Could you maybe link the phase potrait somewhere?
    – mrtaurho
    Jul 22 at 16:58










  • ibb.co/cDCyby This is the phase portrait.
    – SleepApnea
    Jul 22 at 17:30
















based on my general solution: e^t(c1(2,1)+c2(t(2,1)+(-4,0)). Then if we use the IVP and plug in t = 0, I get (1,1) = c1(2,1) + c2(-4,0). I don't really understand how to isolate C1 and C2.
– SleepApnea
Jul 22 at 15:36





based on my general solution: e^t(c1(2,1)+c2(t(2,1)+(-4,0)). Then if we use the IVP and plug in t = 0, I get (1,1) = c1(2,1) + c2(-4,0). I don't really understand how to isolate C1 and C2.
– SleepApnea
Jul 22 at 15:36













Just cosider it as a system of the two equations $1=c_1-4c_2$ and $1=-4c_1$
– mrtaurho
Jul 22 at 15:44




Just cosider it as a system of the two equations $1=c_1-4c_2$ and $1=-4c_1$
– mrtaurho
Jul 22 at 15:44












Based on the phase portrait of this particular case, can I argue that when t either moves to infinity or negative infinity, the phase portrait is moving tangentially inwards towards the origin.
– SleepApnea
Jul 22 at 16:54




Based on the phase portrait of this particular case, can I argue that when t either moves to infinity or negative infinity, the phase portrait is moving tangentially inwards towards the origin.
– SleepApnea
Jul 22 at 16:54












Could you maybe link the phase potrait somewhere?
– mrtaurho
Jul 22 at 16:58




Could you maybe link the phase potrait somewhere?
– mrtaurho
Jul 22 at 16:58












ibb.co/cDCyby This is the phase portrait.
– SleepApnea
Jul 22 at 17:30





ibb.co/cDCyby This is the phase portrait.
– SleepApnea
Jul 22 at 17:30













 

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