Data Science

Matrix Calculations, Eigen Vector

Q1. Let M be the following matrix:

 

(a) Find the inverse of M.

 

To find the inverse of M, we need to find det(A).

det(A) = ad - bc

where

 

det(A) = ad - bc = (2*1) - (-3)(-2) = (2)-(6) = -4

 

Then, rearrange M

 

 

Multiply by 1/det(A)

 

 

This gives M^-1 of:

 

 

 

(b) Using your answer to (a) or otherwise, find the solution to the following system of equations:

 

 

2 ways of solving this question.

 

1) Using M^-1

 

 

2) Using Row Reduction / Subtraction

 

 

 

 

 

(c) Find the eigenvalues of M and their corresponding eigenvectors.

 

 

 

 

 

 

(d) Write down matrices D and P such that D is a diagonal matrix and M = PDP^-1

 

 

Important:

For the eigenvalue in first column D should match the eigenvector in the first column of P

i.e. If lambda1 is in the first column of D, the eigenvector of the corresponding lambda should come in the first column of P.