Eigenvalues and Eigenvectors
Bases

The main property of a
Basisis that every point in the space can be expressed as a linear combination of elements in the basis
Valid Basis 
Invalid Basis
Span
The span of a set of vectors is simply
the set of points that can be reached by walking in the direction of these vectors in any combination
Span of a vector A basis is a minimal spanning set

Minimal Spanning Set 
Number of elements in the basis is the dimension Eigenbases
Some basis are more useful than others

Eigenbases Eigenbases- A special way of linear transformation with respect to a basis that sends a parallelogram to another parallelogram with sides parallel to the original one. The basis is streched in the two directions (in the below case) which is called eigenbasis
Eigenvectors and Eigenvalues In the linear transformation, the two vectors in the basis are called Eigenvectors and the streching factor are called Eigenvalues
Eigenvalues and Eigenvectors
Finding Eigenvalues

Finding Eigenvalues 
Finding Eigenvalues using characteristic polynomial
