Linear Algebra II - Change of Basis

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SUMMARY

The discussion focuses on the change of basis in linear transformations, specifically finding the matrix representation of the transformation T: R3 → R3 defined by T(a,b,c) = (2a-b,b+c,c-3a). The participants clarify the process of determining the matrices MB0(T) and MB(T) using the standard basis B0 and the alternative basis B = {(1,1,0),(1,0,1),(0,1,0)}. The correct matrix representation MB(T) is established as [[4, 4, -1], [-3, -2, 0], [-3, -3, 2]], derived from applying T to the basis vectors and forming the corresponding matrix.

PREREQUISITES
  • Understanding of linear transformations in R3
  • Familiarity with matrix representation of linear transformations
  • Knowledge of basis vectors and change of basis concepts
  • Ability to perform linear combinations of vectors
NEXT STEPS
  • Study the process of finding the matrix representation of linear transformations using different bases
  • Learn about the properties of invertible matrices and their applications in linear algebra
  • Explore the concept of linear combinations and their role in determining matrix coefficients
  • Investigate the implications of change of basis on vector spaces and transformations
USEFUL FOR

Students of linear algebra, educators teaching linear transformations, and anyone seeking to deepen their understanding of change of basis and matrix representations in vector spaces.

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Homework Statement



From Linear Algebra with applications 7th Edition by Keith Nicholson.
Chapter 9.2 Example 2.

Let T: R3 → R3 be defined by T(a,b,c) = (2a-b,b+c,c-3a).
If B0 denotes the standard basis of R3 and B = {(1,1,0),(1,0,1),(0,1,0)}, find an invertible matrix P such that P-1MB0(T)P=MB(T).

Homework Equations




The Attempt at a Solution



I know to find P, I have to first find MB0(T) and MB(T).

MB0(T) is easy because I have to just find each a, b, and c as linear combinations of B0 and the coefficients are MB0(T).

However, I'm not sure how to find MB(T). In the textbook, they write:

MB(T) = [CB(1,1,-3) CB(2,1,-2) CB(-1,1,0)]

I cannot figure out where they came up with these numbers (1,1,-3), (2,1,-2), and (-1,1,0).

Please help. Thank you!

 
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##M_B(T) ## is the 3x 3 matrix where the columns are the result of T on each of the basis vectors.
T(1,1,0) = (1,1,-3).
So your matrix will look like:
##\begin{bmatrix} 1& 2& -1 \\ 1& 1& 1 \\ -3 & -2 & 0 \end{bmatrix}##
 
Oh wow thanks! That was simple.

But in the textbook ##M_B(T)## = ##\begin{bmatrix} 4&4&-1\\-3&-2&0\\-3&-3&2\end{bmatrix}##

From trying to figure out where (1,1,-3) came from, I figured out that (4,-3,-3) came from the coefficients of the linear combination of each of the basis vectors. But is that wrong?
 

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