Solving equations for Eigenvector: Vanishing

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Homework Help Overview

The discussion revolves around solving eigenvector equations derived from a given matrix. Participants are examining the equations resulting from the eigenvalue problem involving the matrix [[9.2196, 6.488], [4.233, 2.9787]] and the eigenvalues λ1 = 0 and λ2 = 12.1983.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to solve the equations 9.2196x + 6.488y = 0 and 4.233x + 2.978y = 0, with some questioning the validity of their approach after multiplying the equations by constants. There is a discussion about the equivalence of the two equations and the implications of normalizing the solution.

Discussion Status

Some participants have provided guidance on the nature of the solutions, indicating that the equations yield the same solution up to a constant multiplier. Others express confusion regarding discrepancies with provided answers in slides and seek further clarification on achieving the correct results.

Contextual Notes

Participants are navigating potential inconsistencies between their calculations and external resources, such as slides, which may present different normalizations or solutions. There is an ongoing exploration of how to reconcile these differences while adhering to the constraints of the eigenvalue problem.

zak100
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Homework Statement


I am trying to solve a Eigen vector matrix:

##\begin{bmatrix}9.2196& 6.488\\4.233& 2.9787\end{bmatrix}\cdot\begin{bmatrix}x\\y\end{bmatrix}-\lambda\begin{bmatrix}x\\y \end{bmatrix}=0##

I have found ##\lambda_1 = 0## and ##\lambda_2 = 12.1983##
However, I can't solve the following equations:
##9.2196x + 6.488y =0 -------(eq.1)##
and ##4.233x + 2.978y =0 ----(eq.2)##

I am multiplying ##(eq.1) ## by ##4.233x## and ##(eq.2)## by ##9.2196##

Some body please guide me how to solve these equations for ##x## and ##y## values.

Zulfi.

Homework Equations


##9.2196x + 6.488y =0 -------(eq.1)##
and ##4.233x + 2.978y =0 ----(eq.2)##​

The Attempt at a Solution


I am multiplying ##(eq.1)## by ##4.233## and ##(eq.2)## by ##9.2196## but both the equations are vanishing. Some body please guide me.

Zulfi.
 
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zak100 said:

Homework Statement


I am trying to solve a Eigen vector matrix:

##\begin{bmatrix}9.2196& 6.488\\4.233& 2.9787\end{bmatrix}\cdot\begin{bmatrix}x\\y\end{bmatrix}-\lambda\begin{bmatrix}x\\y \end{bmatrix}=0##

I have found ##\lambda_1 = 0## and ##\lambda_2 = 12.1983##
However, I can't solve the following equations:
##9.2196x + 6.488y =0 -------(eq.1)##
and ##4.233x + 2.978y =0 ----(eq.2)##

I am multiplying ##(eq.1) ## by ##4.233x## and ##(eq.2)## by ##9.2196##

Some body please guide me how to solve these equations for ##x## and ##y## values.

Zulfi.

Homework Equations


##9.2196x + 6.488y =0 -------(eq.1)##
and ##4.233x + 2.978y =0 ----(eq.2)##​

The Attempt at a Solution


I am multiplying ##(eq.1)## by ##4.233## and ##(eq.2)## by ##9.2196## but both the equations are vanishing. Some body please guide me.

Zulfi.

The two equations are equivalent. So, you just take the solution of either one.
 
And, it only determines the solution up to a constant multiplier, so you can for example arbitrarily set ##x=1## and then find ##y##.
 
Hi,
Thanks for your response. Answer is different in the slide. I have attached the slide. Please guide me.

Solving Decimal eq for Eigen vectors LDA vanishing_PicOfSlide.jpg
 

Attachments

  • Solving Decimal eq for Eigen vectors LDA vanishing_PicOfSlide.jpg
    Solving Decimal eq for Eigen vectors LDA vanishing_PicOfSlide.jpg
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In the solution for ##w_1##, the ratio of the components ##\frac{0.8178}{0.5755}## is the same as the ratio ##\frac{9.2196}{6.488}## in your system of equations. So it's the same answer but with different normalization, one where ##x^2 + y^2 = 1##.
 
Hi,
##lambda_2 =12.1983##
I am not able to get the correct answer.

##9.2196x + 6.488y = 12.1983x ##
##9.216x - 12.1983x = -6.488y ##

##\begin{bmatrix}x\\y\end {bmatrix} = \begin{bmatrix}2.7\\1\end{bmatrix}##

Somebody please guide me how can i get the correct answer?
Zulfi.
 

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