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'''Tricks for checking Linear Independence, Span and Basis'''
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'''Tricks for checking Linear Independence, Span and Basis'''  
  
<u>'''Linear Independence'''</u>
 
  
If det(vectors)&nbsp;!= 0 ⇔ '''linearly independent'''<br>If end result of the rref(vectors) gives [0 0 0 1] -&gt; it is linearly independent because the system is '''inconsistent'''
 
  
If det(vectors) = 0 ⇔ linearly dependent<br>If end result of the rref(vectors) is in the order of [0 0 0 0] and provided the system is consistent, the vectors are '''linearly dependent.'''
 
  
Tip: If #No of vectors &gt; Dimension ⇔ it is '''linearly dependent'''<br>
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<u>'''Linear Independence'''</u>  
  
<u>'''Span'''</u><br>Tip: If the question asks if a vector “belongs to span” of other vectors, then it means it is asking if it’s '''linearly dependent'''
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If det(vectors)&nbsp;!= 0 ⇔ '''linearly independent'''<br>  
  
If Dimension &gt; #No of vectors -&gt; '''it CANNOT span'''
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If det(vectors) = 0 ⇔ '''linearly dependent'''<br>If end result of the rref(vectors) is in the order of [0 0 0 0] and provided the system is consistent, the vectors are '''linearly dependent.'''  
  
If det(vectors)&nbsp;!= 0 ⇔ it spans<br>If end result of the rref(vectors) is in the order of [0 0 0 | 0] and provided the system is consistent, the vectors '''span.'''
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Tip: If #No of vectors &gt; Dimension ⇔ it is '''linearly dependent'''<br>
  
If det(vectors) = 0 ⇔ '''does not span'''<br>If end result of the rref(vectors) gives [0 0 0 | 1] -&gt; it does not span because the system is inconsistent
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<u>'''Span'''</u>  
  
<u>'''Basis'''</u><br>
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If Dimension &gt; #No of vectors -&gt; '''it CANNOT span'''
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If det(vectors)&nbsp;!= 0 ⇔ it spans<br>If end result of the rref(vectors) gives you a matrix with all rows having leading 1's, '''it spans'''.
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If det(vectors) = 0 ⇔ '''does not span'''<br>If end result of the rref(vectors) gives you a matrix with not all rows having a leading 1, it '''does not span.'''
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<u>'''Basis'''</u><br>  
  
 
<br>If Dimension &gt; #No of vectors ⇔ cannot span ⇔ is not a basis  
 
<br>If Dimension &gt; #No of vectors ⇔ cannot span ⇔ is not a basis  
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If #No of vectors &gt; Dimension -&gt; it has to be linearly dependent to span (check the tip)  
 
If #No of vectors &gt; Dimension -&gt; it has to be linearly dependent to span (check the tip)  
  
If #No of vectors = Dimension -&gt; it has to be linearly independent to span<br>
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If #No of vectors = Dimension -&gt; it has to be linearly independent to span<br>  
  
 
[[Category:MA265Spring2011Momin]]
 
[[Category:MA265Spring2011Momin]]

Revision as of 08:15, 1 May 2011

Tricks for checking Linear Independence, Span and Basis



Linear Independence

If det(vectors) != 0 ⇔ linearly independent

If det(vectors) = 0 ⇔ linearly dependent
If end result of the rref(vectors) is in the order of [0 0 0 0] and provided the system is consistent, the vectors are linearly dependent.

Tip: If #No of vectors > Dimension ⇔ it is linearly dependent

Span

If Dimension > #No of vectors -> it CANNOT span

If det(vectors) != 0 ⇔ it spans
If end result of the rref(vectors) gives you a matrix with all rows having leading 1's, it spans.

If det(vectors) = 0 ⇔ does not span
If end result of the rref(vectors) gives you a matrix with not all rows having a leading 1, it does not span. Basis


If Dimension > #No of vectors ⇔ cannot span ⇔ is not a basis

If #No of vectors > Dimension -> it has to be linearly dependent to span (check the tip)

If #No of vectors = Dimension -> it has to be linearly independent to span

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