table of contents

linear map

2023-12-22

a linear map from to is a function with the following properties.

some stuff from college

let be vector spaces over the field , and let be a function which would be called a linear map if:

  1. for every ,
  2. for every and ,

let be a linear transformation,

consider the transformation of the 2d plane : where this transformation maps the line , where or to the line

use the lines parametric form to find the image of an arbitrary point on the original line, then convert the obtained parametric coordinates of the image into an implicit equation

is a linear map?

we need to prove

i should be writing not

we need to prove

check whether this represents a linear map:

it isnt, a counter example:

if is a linear map then

if is a function such that then isnt a linear map

if is a linear map then:

  1. the kernel of is
  2. the image of is , which means all the values that can be returned by , which is also the column space of its corresponding transformation matrix (if it has one)

given the linear operator defined by

find the matrix of in the basis

on the left columns of the matrix lies the basis and on the right 4 columns lies the image

A=matrix(QQ, [[1,1,0,0, 2,0,1,0], [1,-1,1,0, 2,-1,0,1], [1,0,-1,1, 2,0,-1,0], [1,0,0,-1, 2,1,0,-1]]); fm(r'\[{A} \implies {A.echelon_form()}\]') and so the matrix is:

fm(r'\[[L]_A^B = {A.echelon_form().submatrix(0,4,4,4)}\]')

find the bases of

finding the basis of

to find the basis of we reduce the matrix:

and so the basis of is and

we apply a simple check:

given the linear operator defined by such that

find the matrix of in the basis

find the bases of

given the function defined by

prove is a linear transformation

's domain is a vector space of polynomials of the second degree at most,

assume , need to prove

let , need to prove

therefore, indeed is a linear transformation

find the matrix of in standard basis form

find the bases of