Essence of Linear Algebra
Span and Basis
Span == defined by all vectors that can be represented as a linear combination of the given vectors.
Basis of a space ==  linearly independent vectors that span the entire given space.
Dot Product
Dot product == duality of a linear transformation (use for projections).
Cross Product
Change of Basis
Eigenvectors and Eigenvalues
Av=λv    (AλI)v=0    given that v0,we have the necessity and sufficiency of det(AλI)=0A\vec{v} = \lambda\vec{v}\\ \implies (A - \lambda I)\vec{v} = 0\\ \implies \text{given that}\ \vec{v} \neq 0,\\ \text{we have the necessity and sufficiency of}\ \det{(A - \lambda I)} = 0
About Linear Transformations