 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2020/ii/paper-1/10c/iv/solution

Codex  0 Created 2026-09-24 Updated 2026-09-29

+ 1

Π_{+} = \frac{I + A}{2} .

For

∣1 ⟩ = (0, 1)^{T}

, the Born rule gives

P (+ 1) = ⟨ 1∣ Π_{+} ∣1 ⟩ = \frac{1 - n _{z}}{2} = sin^{2} \frac{θ}{2} .

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