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A First Course in Linear Algebra, 2017a

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528 Vector Spaces<br />

⎡<br />

(a) T ⎣<br />

⎡<br />

(b) T ⎣<br />

⎡<br />

(c) T ⎣<br />

⎡<br />

(d) T ⎣<br />

x<br />

y<br />

z<br />

x<br />

y<br />

z<br />

x<br />

y<br />

z<br />

x<br />

y<br />

z<br />

⎤<br />

⎦ =<br />

⎤<br />

[ x + 2y + 3z + 1<br />

2y − 3x + z<br />

⎦ =<br />

[<br />

x + 2y 2 + 3z<br />

2y + 3x + z<br />

⎤<br />

⎦ =<br />

⎤<br />

⎦ =<br />

]<br />

[<br />

s<strong>in</strong>x + 2y + 3z<br />

2y + 3x + z<br />

[ x + 2y + 3z<br />

2y + 3x − lnz<br />

]<br />

]<br />

]<br />

Exercise 9.9.10 Suppose<br />

[<br />

A1 ··· A n<br />

] −1<br />

exists where each A j ∈ R n and let vectors {B 1 ,···,B n } <strong>in</strong> R m be given. Show that there always exists a<br />

l<strong>in</strong>ear transformation T such that T(A i )=B i .<br />

Exercise 9.9.11 F<strong>in</strong>d the matrix for T (⃗w)=proj ⃗v (⃗w) where ⃗v = [ 1 −2 3 ] T .<br />

Exercise 9.9.12 F<strong>in</strong>d the matrix for T (⃗w)=proj ⃗v (⃗w) where ⃗v = [ 1 5 3 ] T .<br />

Exercise 9.9.13 F<strong>in</strong>d the matrix for T (⃗w)=proj ⃗v (⃗w) where ⃗v = [ 1 0 3 ] T .<br />

{[ ] [ ]}<br />

[ ]<br />

2 3<br />

Exercise 9.9.14 Let B = , be a basis of R<br />

−1 2<br />

2 5<br />

and let ⃗x = be a vector <strong>in</strong> R<br />

−7<br />

2 .F<strong>in</strong>d<br />

C B (⃗x).<br />

⎧⎡<br />

⎤ ⎡ ⎤ ⎡ ⎤⎫<br />

⎡ ⎤<br />

⎨ 1 2 −1 ⎬<br />

5<br />

Exercise 9.9.15 Let B = ⎣ −1 ⎦, ⎣ 1 ⎦, ⎣ 0 ⎦<br />

⎩<br />

⎭ be a basis of R3 and let⃗x = ⎣ −1 ⎦ be a vector<br />

2 2 2<br />

4<br />

<strong>in</strong> R 2 .F<strong>in</strong>dC B (⃗x).<br />

([ ]) [ ]<br />

a a + b<br />

Exercise 9.9.16 Let T : R 2 ↦→ R 2 be a l<strong>in</strong>ear transformation def<strong>in</strong>ed by T = .<br />

b a − b<br />

Consider the two bases<br />

{[ ] [ ]}<br />

1 −1<br />

B 1 = {⃗v 1 ,⃗v 2 } = ,<br />

0 1<br />

and<br />

{[<br />

1<br />

B 2 =<br />

1<br />

] [<br />

,<br />

1<br />

−1<br />

F<strong>in</strong>d the matrix M B2 ,B 1<br />

of T with respect to the bases B 1 and B 2 .<br />

]}

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