 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2026/ia/paper-1/8b/b/solution

Codex  0 Created 2026-09-24 Updated 2026-09-25

Because

(n \cdot σ)^{2} = I

, even and odd powers sum separately:

R = I cos θ + i (n \cdot σ) sin θ

. Then

R R^{†} = I

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