Questions
Question 1
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What two properties must a list have to be a basis for a vector space \(V\)?
Question 2
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Why is \(\{(1,0),(0,1)\}\) called the standard basis of \(\mathbb R^2\)?
Question 3
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Can \(\{(1,0),(2,0)\}\) be a basis for \(\mathbb R^2\)?
Question 4
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Is a single non-zero vector a basis for the line it spans?
Question 5
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Check whether \(B=\{(1,1),(1,-1)\}\) is a basis for \(\mathbb R^2\).
Question 6
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Check whether \(B=\{(1,2),(2,4)\}\) is a basis for \(\mathbb R^2\).
Question 7
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Find a basis for \(W=\{(x,y,0):x,y\in\mathbb R\}\).
Question 8
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Find a basis for the line \(L=\{t(2,-3,1):t\in\mathbb R\}\).
Question 9
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Show that \(B=\{(1,0,1),(0,1,1),(0,0,1)\}\) is a basis for \(\mathbb R^3\).
Question 10
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Decide whether \(\{1,x,x^2\}\) is a basis for \(P_2\), the polynomials of degree at most \(2\).
Question 11
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Explain why a basis gives unique coordinates.
Question 12
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Why is a spanning list with a redundant vector not a basis? Use \((1,0),(0,1),(1,1)\).
Question 13
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For which \(k\) is \(\{(1,1),(1,k)\}\) a basis for \(\mathbb R^2\)?
Question 14
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For which \(a\) is \(\{(1,0,a),(0,1,a),(1,1,2a)\}\) a basis for \(\mathbb R^3\)?
Question 15
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For which \(t\) is \(B_t=\{(1,0,0),(0,1,0),(1,1,t)\}\) a basis for \(\mathbb R^3\)?
Question 16
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For which \(a\) is \(\{1+x,1+ax\}\) a basis for \(P_1\)?
Question 17
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For which \(b\) do \((1,0,b),(0,1,b),(1,1,1)\) form a basis for \(\mathbb R^3\)?
Question 18
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A student says every spanning set is a basis. Diagnose the error.
Question 19
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Prove that if a list is a basis, no vector in the list can be removed without losing spanning.
Question 20
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Prove that if a list is a basis, adding any vector from the same space makes the enlarged list dependent.