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Question

Philoid · Accepted Answer

To find: Value of

Formula used: i² = -1

We have,

On expanding the above,

⇒ (a + ib) (a – ib) – (-c + id) (c + id)

⇒ (a² – iab + iba – i²b²) - (-c² – icd + icd + i²d²)

⇒ {a² – iab + iba – (-1)b²} – {-c² – icd + icd + (-1)d²}

⇒ {a² – iab + iba + 1b²} – {-c² – icd + icd - 1d²}

⇒ a² + b² + c² + d²