GATE | GATE-CS-2014-(Set-1) | Question 4

IF (z + 1/z)² = 98, compute (z² + 1/z²)
(A) 96
(B) 99
(C) 100
(D) 94


Answer: (A)

Explanation: (z + 1/z)² = (z² + 1/z²) + 2*z*1/z
(z² + 1/z²) = (z + 1/z)² – 2 = 98 – 2 = 96

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