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fibonacci_sequence [2023/07/26 14:57] – [Eigen vectors of A] rajufibonacci_sequence [2023/08/05 11:05] (current) – [References] raju
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 \left( \lambda_1, \lambda_2 \right) = \left( \frac{1+\sqrt{5}}{2}, \frac{1-\sqrt{5}}{2} \right) \left( \lambda_1, \lambda_2 \right) = \left( \frac{1+\sqrt{5}}{2}, \frac{1-\sqrt{5}}{2} \right)
 $$ $$
 +Also, note
 +$$ \lambda_1 - \lambda_2 = \sqrt{5} $$
  
 ==== Eigen vectors of A ==== ==== Eigen vectors of A ====
Line 62: Line 64:
 \end{bmatrix} \end{bmatrix}
 $$ $$
 +
 Expanding Expanding
-$$+
 \begin{align} \begin{align}
 (1-\lambda) x_1 + x_2 & = 0 \\ (1-\lambda) x_1 + x_2 & = 0 \\
 x_1 & = \lambda x_2 x_1 & = \lambda x_2
 \end{align} \end{align}
-$$ 
  
 From the characteristic equation of $ \mathbf{A} $, we know From the characteristic equation of $ \mathbf{A} $, we know
-$$ +
 \begin{align} \begin{align}
 & (1-\lambda)(-\lambda) - 1 = 0 \\ & (1-\lambda)(-\lambda) - 1 = 0 \\
 \Rightarrow \quad & (1-\lambda) = -\frac{1}{\lambda} \Rightarrow \quad & (1-\lambda) = -\frac{1}{\lambda}
 \end{align} \end{align}
-$$+
 Substituting for $1-\lambda$, we get Substituting for $1-\lambda$, we get
  
-$$ 
 \begin{align} \begin{align}
 -\frac{1}{\lambda} x_1 + x_2 & = 0 \\ -\frac{1}{\lambda} x_1 + x_2 & = 0 \\
 x_1 & = \lambda x_2 x_1 & = \lambda x_2
 \end{align} \end{align}
-$$ 
  
 So both equations simplify to So both equations simplify to
 $$ x_1 = \lambda x_2$$ $$ x_1 = \lambda x_2$$
  
 +which gives the eigen vector matrix as
 +$$
 +\Lambda = 
 +\begin{bmatrix}
 +\lambda_1 & \lambda_2 \\
 +1 & 1
 +\end{bmatrix}
 +$$
 +
 +
 +==== References ====
 +  * https://www.dokuwiki.org/plugin:mathjax - mathjax syntax of dokuwiki
 +  * https://tex.stackexchange.com/questions/162533/how-to-align-implies-that-symbols-neatly-in-equation-array - talks about alignat which can be used to align 'implies that' symbols in an equation array. I picked up ''\Rightarrow\quad'' from here.
 +  * https://mathworld.wolfram.com/CharacteristicEquation.html
 +  * https://www.math-linux.com/latex-26/faq/latex-faq/article/how-to-write-matrices-in-latex-matrix-pmatrix-bmatrix-vmatrix-vmatrix - nice visual representation of how various matrix environments work in latex
 +  * https://tex.stackexchange.com/questions/78736/bigger-parentheses-in-equations - picked up ''\left( ... \right)'' from here.
 +    * tags | big parentheses
  
fibonacci_sequence.1690383472.txt.gz · Last modified: 2023/07/26 14:57 by raju