Quantity comprised of a direction and magnitude.
Span of Vectors
All the vectors that can be created from a set of vectors.
Vectors are linearly dependent if you can remove one and not reduce the span. One of the vectors can be produced by a linear combination of the others. Otherwise they are linearly independent if each vector adds a new dimension to the span.
aka. Inner Product of Two vectors. Used to find the angle between two vectors.
a x b = -b x a X x X = 0 Orthogonal to initial vectors
Linearly independent vectors in a vector space that, when linearly combined, makes up all of the other vectors in the space. In more general terms, a basis is a linearly independent spanning set.
In a normed vector space is a vector of length 1. Unit Vectors pointing x, y, z =
Two vectors are parallel if one is a scalar multiple of the other.
When dot-product of two different vectors is close to 0.
Two vectors which are orthogonal and of length 1 are said to be orthonormal.
Orthogonality is the generalization of the notion of perpendicularity.
The transpose AT of an m×n matrix A is the n×m matrix whose (i,j)-entry is aji.
P = radius cos alpha, r sin alpha P' = r cos(alpha + theta), r sin(alpha + theta)
Like cube, but doesn't have to be all equal.
Formal Linear Properties
Linear transformation is a transformation that preserves spacing. For example a projects of dots in 2D with space 1 projected onto 1D still have spacing of 1.
Singular Value Decomposition SVD
Matrix where vectors are orthogonal.
How much a transformation scales a matrix by. If negative, "flips" the axis then scales. When the determinant is 0 the matrix is not invertible. Meaning there is no matrix to multiply it by to give the identity.
import sympy as sp a, b, c, d = sp.symbols('a,b,c,d') A = sp.Matrix([[a,b], [c,d]]) A.det() # Print what this would look like in latex sp.latex(A) sp.latex(A.det())
Eigenvalues and Eigenvectors
A scalar \(\lambda\) (eigenvalue) when multiplied by an eigenvector is equal to the original matrix A multiplied by the eigenvector.
on \(\det(A - \lambda I_3) = 0\), i.e.
Two or more vectors with scalar weights multipled and added.
The Frobenius norm