Linear Algebra matrix linear transformation

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Homework Help Overview

The discussion revolves around a linear transformation T defined from the vector space of polynomials of degree at most 2, P2, to itself. Participants are tasked with finding the coordinate matrix of T relative to a specified ordered basis. The transformation is expressed in terms of its action on a polynomial represented by its coefficients.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss how to apply the transformation T to each basis vector in the ordered basis E. There are attempts to clarify the correct application of the transformation and the representation of the basis vectors. Some participants express confusion regarding the notation and the transformation's definition.

Discussion Status

There is ongoing exploration of how to correctly apply the transformation to the basis vectors. Some participants have provided partial calculations, while others are questioning the correctness of their results. The discussion reflects a mix of interpretations and attempts to clarify the steps involved in finding the coordinate matrix.

Contextual Notes

Participants mention issues with formatting and notation, as well as confusion regarding the use of different symbols (e.g., f instead of e) in the context of the problem. There is a recognition that the same basis is used in both the domain and codomain of the transformation.

Rifscape
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Homework Statement


Consider the linear transformation T from
V = P2
to
W = P2
given by
T(a0 + a1t + a2t2) = (−4a0 + 2a1 + 3a2) + (2a0 + 3a1 + 3a2)t + (−2a0 + 4a1 + 3a2)t^2
Let E = (e1, e2, e3) be the ordered basis in P2 given by
e1(t) = 1, e2(t) = t, e3(t) = t^2
Find the coordinate matrix [T]EE of T relative to the ordered basis E used in both V and W, that is, fill in the blanks below: (Any entry that is a fraction should be entered as a proper fraction, i.e. as either x/y or -x/y where x and y are positive integers with no factors in common.)
T(e1(t)) = _e1(t) + _ e2(t) + _e3(t)
T(e2(t)) = _e1(t) + _e2(t) + _e3(t)
T(e3(t)) = _e1(t) + _e2(t) + _e3(t)
and therefore :
[T]EE = the combined matrix of the coefficients of the above three equations.

Sorry for the poor formatting

Homework Equations


No idea

The Attempt at a Solution


I have no idea
I have no idea how to do this, if someone can give me a step by step solution so that I can understand each step and process I would appreciate it greatly.
Thanks for your help.
 
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Rifscape said:

Homework Statement


Consider the linear transformation T from
V = P2
to
W = P2
given by
T(a0 + a1t + a2t2) = (−4a0 + 2a1 + 3a2) + (2a0 + 3a1 + 3a2)t + (−2a0 + 4a1 + 3a2)t^2
You mean T(a0+ a1t+ a2t^2) on the left, right?

Let E = (e1, e2, e3) be the ordered basis in P2 given by
e1(t) = 1, e2(t) = t, e3(t) = t^2
Find the coordinate matrix [T]EE of T relative to the ordered basis E used in both V and W, that is, fill in the blanks below: (Any entry that is a fraction should be entered as a proper fraction, i.e. as either x/y or -x/y where x and y are positive integers with no factors in common.)
T(e1(t)) = _e1(t) + _ e2(t) + _e3(t)
T(e2(t)) = _e1(t) + _e2(t) + _e3(t)
T(e3(t)) = _e1(t) + _e2(t) + _e3(t)
and therefore :
[T]EE = the combined matrix of the coefficients of the above three equations.

Sorry for the poor formatting

Homework Equations


No idea

The Attempt at a Solution


I have no idea
I have no idea how to do this, if someone can give me a step by step solution so that I can understand each step and process I would appreciate it greatly.
Thanks for your help.
To find the matrix corresponding to a linear transformation in a given ordered basis, apply that linear transformation to each basis vector in turn and write the result as a linear combination of those basis vectors. The coefficients give a column of the basis. For example, to apply the linear transformation two the first basis vector, T(e1), note that e1= 1+ 0t+ 0t^2. That is, a0= 1, a1= 0, and a2= 0. Since T is defined by "T(a0 + a1t + a2t2) = (−4a0 + 2a1 + 3a2) + (2a0 + 3a1 + 3a2)t + (−2a0 + 4a1 + 3a2)t^2". T(1+ 0t+ 0t^2)= (-4(1)+ 2(0)+ 3(0))+ (2(1)+ 3(0)+ 3(0))t+ (-2(1)+ 4(0)+ 3(0))t^2= -4+ 2t- 2t^2. The first column of the matrix is \begin{pmatrix}-4 \\ 2 \\ -2\end{pmatrix}.

Now do the same to the second and third basis vectors.
 
T(f1(t)) = f1(t) + f2(t) + f3(t)
When I put in the first one which is f1(t) = 1, so it would be 1 + 0t + 0t^2. So when I plug it in, I should get (2(1) + 0 + 0) + (2(1) + 0 + 0)t + (-2(1) + 0 + 0)t^2
= (2,2,-2) However when I put this in it is wrong, does it have something to do with how f2(t) is now 1 + t, and f3(t) is now 1 + t + t^2?
T(f2(t)) = f1(t) + f2(t) + f3(t)
T(f3(t)) = f1(t) + f2(t) + f3(t)
 
Rifscape said:
T(f1(t)) = f1(t) + f2(t) + f3(t)
When I put in the first one which is f1(t) = 1, so it would be 1 + 0t + 0t^2. So when I plug it in, I should get (2(1) + 0 + 0) + (2(1) + 0 + 0)t + (-2(1) + 0 + 0)t^2
= (2,2,-2) However when I put this in it is wrong, does it have something to do with how f2(t) is now 1 + t, and f3(t) is now 1 + t + t^2?
T(f2(t)) = f1(t) + f2(t) + f3(t)
T(f3(t)) = f1(t) + f2(t) + f3(t)

So, you have ##T(e_1) = 2 e_1 + 2 e_2 - 2 e_3##. Why do you think this is wrong?
 
When I enter the numbers in it says it is wrong, except the - 2 at the end which is right. I feel like I am doing something wrong since f2(t) is now 1+t.
 
Rifscape said:
T(f1(t)) = f1(t) + f2(t) + f3(t)
When I put in the first one which is f1(t) = 1, so it would be 1 + 0t + 0t^2. So when I plug it in, I should get (2(1) + 0 + 0) + (2(1) + 0 + 0)t + (-2(1) + 0 + 0)t^2
= (2,2,-2) However when I put this in it is wrong, does it have something to do with how f2(t) is now 1 + t, and f3(t) is now 1 + t + t^2?
T(f2(t)) = f1(t) + f2(t) + f3(t)
T(f3(t)) = f1(t) + f2(t) + f3(t)
Where did f1, f2, and f3 come from? The same basis, i.e., ##e_1, e_2,## and ##e_3## is used in both V and W. In this problem V and W are the same spaces.
You aren't using the definition of the transformation, which I've copied below.
##T(a_0 + a_1t + a_2t^2) = (−4a_0 + 2a_1 + 3a_2) + (2a_0 + 3a_1 + 3a_2)t + (−2a_0 + 4a_1 + 3a_2)t^2##
Use this definition to see what T does to ##e_1## (HallsOfIvy already did this one), ##e_2##, and ##e_3##.
 
No sorry I didn't clarify. I finished the last question, this is a completely new question. I solved the previous question with hall of ivys help. However when I apply the same strategy to this question I cannot solve it. This question has f instead of e. Sorry for the confusion
 
Rifscape said:
No sorry I didn't clarify. I finished the last question, this is a completely new question.
I solved the previous question with hall of ivys help. However when I apply the same strategy to this question I cannot solve it. This question has f instead of e. Sorry for the confusion
Then you should start a new thread, with the complete problem statement of the new problem.
 

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