 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2026/ii/paper-2/20g/e/solution

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

R = Z [5]

, take

I = J_{1} = (2, 1 + 5)

and

J_{2} = (2)

. Direct multiplication gives

I^{2} = (4, 2 + 25, 6 + 25) = 2 I = I J_{2}

, but

I \neq = (2)

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