6. Which one is not a root of the fourth root of unity.
(a) i
(b) 1
(c) i/√2
(d) -i
7. If z3 – 2z2 + 4z – 8 = 0 then :
(a) |z| = 1
(b) |z| = 2
(c) |z| = 3
(d) none
8. i1 + i2 + i3 + i4 + ……… + i1000 =
(a) 0
(b) 1
(c) -1
(d) none
9. If the cube roots of unity are 1,ω,ω2 then 1 + ω + ω2 =
(a) 0
(b) 1
(c) -1
(d) ω
10. The small positive integer ‘n’ for which (1+i)2n = (1-i)2n is :
(a) 2
(b) 4
(c) 8
(d) 12
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