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Question:

Let zk = cos(2kπ/10) + i sin(2kπ/10); k = 1, 2, ..., 9. List - I List - II
(P) For each zk there exists a zj such that zkzj = 1
(Q) There exists a k ∈ {1, 2, ..., 9} such that z1z = zk has no solution z in the set of complex numbers
(R) |1 - z1||1 - z2|...|1 - z9|/10
(S) 1 - Σ9k=1 cos(2kπ/10)

P-1, Q-2, R-4, S-3

P-2, Q-1, R-4, S-3

P-2, Q-1, R-3, S-4

P-1, Q-2, R-3, S-4

Solution:

(P)zkis 10throot of unity⇒¯Zkwill also be 10throot of unity. Takezjas¯zk.