Differential Equations and Linear Algebra (4th Edition)

Published by Pearson
ISBN 10: 0-32196-467-5
ISBN 13: 978-0-32196-467-0

Chapter 6 - Linear Transformations - 6.5 The Matrix of a Linear Transformation - Problems - Page 427: 13

Answer

See below

Work Step by Step

From Theorem 6.4.5: $$[T(p(x))]_C=[T]^C_B[p(x))]_B$$ a) Computing $[T]^C_B$ $T(1)=1'=0\\ T(x)=1\\ T(x^2)=(x^2)'=2x\\ T(x^3)=(x^3)'=3x^2\\ T(x^4)=(x^4)'=4x^3$ then we have $T(1)=0=0.1+0.x+0.x^2+0.x^3\\ T(x)=1=1.1+0.x+0.x^2+0.x^3\\ T(x^2)=2x=0.1+2.x+0.x^2+0.x^3\\ T(x^3)=3x^2=0.1+0.x+3.x^2+0.x^3\\ T(x^4)=4x^3=0.1+0.x+0.x^2+4.x^3$ Therefore, $[T(1)]_C=\begin{bmatrix} 0 \\ 0 \\ 0 \\ 0 \end{bmatrix}\\ [T(x)]_C=\begin{bmatrix} 1 \\ 0 \\ 0 \\ 0 \end{bmatrix}\\ [T(x^2)]_C=\begin{bmatrix} 0 \\ 2 \\ 0 \\ 0 \end{bmatrix}\\ [T(x^3)]_C=\begin{bmatrix} 0 \\ 0 \\ 3 \\ 0 \end{bmatrix} \\ [T(x^4)]_C=\begin{bmatrix} 0 \\ 0 \\ 0 \\ 4 \end{bmatrix}$ Hence, $[T]_B^C=\begin{bmatrix} 0 & 1 & 0 & 0 &0 \\ 0 & 0 & 2 & 0 & 0\\ 0 & 0 & 0 & 3 & 0 \\ 0 & 0 & 0 & 0 & 4 \end{bmatrix}$ We can notice that $[p(x)]_B=\begin{bmatrix} 3 \\ -4\\ 6 \\ 6 & 2 \end{bmatrix}$ Consequently, $[T(v)]_C=[T]^C_B[p(x)]_B=\begin{bmatrix} 0 & 1 & 0 & 0 &0 \\ 0 & 0 & 2 & 0 & 0\\ 0 & 0 & 0 & 3 & 0 \\ 0 & 0 & 0 & 0 & 4 \end{bmatrix}\begin{bmatrix} 3 \\ -4\\ 6 \\ 6 & 2 \end{bmatrix}=\begin{bmatrix} -4 \\ 12 \\ 18 \\ -8 \end{bmatrix}\\ \rightarrow T(p(x))=-4+12x+18x^2-8x^3$ b) From part (a), we obtain: $T(p(x))=T(3-4x+6x^2+6x^3-2x^4)=(3-4x+6x^2+6x^3-2x^4)'=-4+12x+18x^2-8x^3$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.