 Solution

ID: past-exam-of-the-year-1-of-the-computer-science-course-of-the-university-of-oxford/2018/digital-systems-linear-algebra-introduction-to-formal-proof/4/b/iii/solution

The reduced equations are

x + z = 0

and

y + 2 z = 0

. Thus the null space is the line

ker A = ⎩ ⎨ ⎧ t - 1 - 2 1 : t \in R ⎭ ⎬ ⎫ .

The nonzero spanning vector gives a one-element basis, so the nullity is one.

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