1.8 Intro to Linear Transformation/ 1.9 Matrix for a Linear Transformation Flashcards
Transformation
function T: Rn –> Rm
domain of transformation for T: Rn –> Rm
Rn
codomain of transformation for T: Rn –> Rm
Rm
matrix transformation
a transformation T: Rn –> Rm where T(x) = Ax and A is an m x n matrix
A transformation T: Rn –> Rm is a linear transformation if:
( 1 ) for all vectors x, y belong to Rn, T(x+y)=T(x)+T(y)
2 ) for all vector x belong to Rn and for all c belong to R, T(cx)=cT(x
Image
Let T: Rn –> Rm be a transformation. The image of x belong to Rn is T(x)
IMAGE = OUTPUT
Image of T
the set ImT = {T(x) such that x belong to Rn}
range does not equal codomain
Linear transformation and matrix transformation relation?
a linear transformation T: Rn –> Rm is EQUIVALENT to the matrix transformation x|–> Ax where A is an m x n matrix
standard matrix
[ T(e1) T(e1) …. T(en) ]
for a transformation T: Rn –> Rm:
( 1 ) if the image is Rm then we say T is onto or subjective
( 2 ) if T(x1) = T(x2) implies x1=x2 then we say T is one to one or injective
If T is onto then
- T(x)=b has a solution for all b belonging to Rm
- A HAS A PIVOT IN EVERY ROW
If T is one to one then
- Ax = b has at most one solution
- A HAS A PIVOT IN EVERY COLUMN
Suppose T: Rn –> Rm is a linear transformation with standard matrix A
( 1 ) T is onto if and only if the columns of A span Rm
( 2 ) T is one to one if and onl if the columns of A are linearly independent