 Solution

ID: past-exam-of-the-mathematical-methods-i-course-of-the-university-of-oxford/2014/2/solution

a^{2} - i (- i) = a^{2} - 1

A^{- 1} = \frac{1}{a ^{2} - 1} (a i - i a), a \neq = \pm 1.

When

a = 1

a = - 1

we have a singular matrix, so no inverse matrix exists. This criterion holds for real or complex

a

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