Questions
Question 1
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What does \([\mathbf v]_B\) mean?
Question 2
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Why must a basis be ordered before coordinates are written?
Question 3
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Find \([(3,4)]_B\) for the standard basis \(B=((1,0),(0,1))\).
Question 4
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If \(B=((0,1),(1,0))\), find \([(3,4)]_B\).
Question 5
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Find coordinates of \((5,1)\) in \(B=((1,1),(1,-1))\).
Question 6
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Check that \([(5,1)]_{((1,1),(1,-1))}=(3,2)\).
Question 7
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Find \([(2,3)]_B\) for \(B=((1,0),(1,1))\).
Question 8
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Find \([(1,2,3)]_B\) for \(B=((1,0,0),(0,1,0),(1,1,1))\).
Question 9
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Find the vector with coordinates \((2,-1)\) in \(B=((1,2),(3,1))\).
Question 10
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For \(B=((1,1),(2,1))\), find \([(4,3)]_B\).
Question 11
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Explain why coordinates in a fixed basis are unique.
Question 12
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A vector has coordinates \((1,2)\) in \(B=((1,0),(1,1))\). Find its standard coordinates and explain the basis dependence.
Question 13
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Find \([(x,y)]_B\) for \(B=((1,1),(1,-1))\).
Question 14
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Find coordinates of \((a,b,c)\) in \(B=((1,0,0),(1,1,0),(1,1,1))\).
Question 15
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For which \(k\) does \(B_k=((1,1),(1,k))\) allow unique coordinates for every vector in \(\mathbb R^2\)?
Question 16
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For which \(t\) is \([(1,2,3)]_{B_t}\) defined for every target vector when \(B_t=((1,0,0),(0,1,0),(1,1,t))\)?
Question 17
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For \(B=((1,0),(1,k))\), find \([(x,y)]_B\) when possible and state the condition on \(k\).
Question 18
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A student writes \([(3,4)]_B=(3,4)\) for every basis \(B\). Give a counterexample.
Question 19
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Prove that changing the order of a basis changes the order of coordinates.
Question 20
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Explain why coordinates describe the same vector, not a different physical displacement.