Single correct option
Let be a non-real cube root of unity. Match each entry of List-I with its value in List-II.
List-I
(P) The number of complex numbers satisfying
(Q) The number of real solutions of
(R) The value of
(S) The value of
List-II
(1) (2) (3) (4) (5)
List-I
(P) The number of complex numbers satisfying
(Q) The number of real solutions of
(R) The value of
(S) The value of
List-II
(1) (2) (3) (4) (5)
- A. P→5, Q→4, R→3, S→1
- B. P→3, Q→5, R→4, S→1
- C. P→5, Q→3, R→4, S→1
- D. P→5, Q→3, R→1, S→4
Show answer and solution
Answer: (C) P→5, Q→3, R→4, S→1
(P) Taking moduli, , so or . For , multiplying by gives , which has roots; with there are , so P→5. (Q) holds at and , and also for one negative , because changes sign between and ; for , exceeds forever, so there are exactly solutions: Q→3. (R) Using : and , so the product is : R→4. (S) The six values are and sum to : S→1. The unmatched item (2) is a distractor. A numerical check of each count and value agrees.
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