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Linear Transformation / Coordinate Vector Question

  • Thread starter Gotejjeken
  • Start date
  • #1
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Homework Statement


The following vectors form an ordered basis E = [v1, v2] of the subspace V = span(v1,v2):

v1 = (1,2,1)^T , v2 = (3,2,1)^T.

The vector v = (24,-8,-4)^T belongs to the subspace V. Find its coordinates (c1,c2)^T = [v]E relative to the ordered basis E = [v1,v2].

Homework Equations



None.

The Attempt at a Solution



I am not quite sure how to approach this problem. I wanted to calculate the inverse of:

1 3
2 2
1 1

and then multiply v = (24, -8, -4)^T by the inverse to get the coordinate vector relative to E, however I have no idea if that is the right approach. I feel I'm missing something...
 

Answers and Replies

  • #2
33,508
5,194

Homework Statement


The following vectors form an ordered basis E = [v1, v2] of the subspace V = span(v1,v2):

v1 = (1,2,1)^T , v2 = (3,2,1)^T.

The vector v = (24,-8,-4)^T belongs to the subspace V. Find its coordinates (c1,c2)^T = [v]E relative to the ordered basis E = [v1,v2].

Homework Equations



None.

The Attempt at a Solution



I am not quite sure how to approach this problem. I wanted to calculate the inverse of:

1 3
2 2
1 1
The only matrices that have inverses are square matrices. The one you show above is 3 x 2, so isn't square.
and then multiply v = (24, -8, -4)^T by the inverse to get the coordinate vector relative to E, however I have no idea if that is the right approach. I feel I'm missing something...
Solve the equation below for the constants c1 and c2.
(24, -8, -4)^T = c1*(1,2,1)^T + c2*(3,2,1)^T
 
  • #3
29
0
Oh, wow. Thank you, it seems I was over-complicating things...the wording of that problem had my brain in knots.
 

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