Single correct option
Let . Match the quantities in List-I with the values in List-II.
List-I
(P)
(Q)
(R)
(S)
List-II
(1)
(2)
(3)
(4)
(5)
List-I
(P)
(Q)
(R)
(S)
List-II
(1)
(2)
(3)
(4)
(5)
- A. P→2, Q→1, R→4, S→3
- B. P→1, Q→2, R→3, S→4
- C. P→2, Q→5, R→3, S→4
- D. P→2, Q→1, R→3, S→4
Show answer and solution
Answer: (D) P→2, Q→1, R→3, S→4
(P) , and , so , which is (2). (Q) The roots of are , ; evaluating at gives , which is (1). (R) Expanding, and the inner sum is when and otherwise, so , which is (3). (S) Since , putting gives , which is (4). Hence P→2, Q→1, R→3, S→4. Numerical evaluation with complex arithmetic gives , , , , all matching. Option (5) is unused. Notice that all four parts use the identity or the orthogonality of roots of unity. A frequent error in (R) is to include more binomial terms than the multiples of five, or to forget the factor five from the sum over .
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