The total mark is 42

PS#12
4 Q1(a)
4 Q1(b)
4 Q1(c)
4 Q1(d)
8 Q2
8 Q3
6 Q5
4 Q6



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1c:  Some people are still forgetting the zero vector.

2:  Only about 4 or 5 considered the case of w1 and w2 being linearly
dependent.

5:  Many did not state why lamda != 0

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- In question one, some people are still forgetting to check that a subspace
is nonempty.
- Very few people got the second question correct. Most of them simply said
that {lambda}_1 w_1 + {lambda}_2 w_2 cannot equal {lambda}(w_1 + w_2) without
justification.
- In question 5, a common error was failing to check that {lambda} is
nonzero.

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generally most marks were lost on Q2,
majority of the students didn't consider the 2 cases,
w1 and w2 linearly independent and
w1 and w2 not lineary independent
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