Q161. The equation 2 z z = has:
A no solution
B two solutions
C four solutions
D infinit number of solutions
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Correct answer: four solutions
Q162. The point z in Argand's plane moves such that Re iz +1 = 2 iz -1 where z = x+iy, the locus of is:
A A straight line
B a circle
C an ellipse
D a hyperbola
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Correct answer: a circle
Q163. If 2 z - = 6 z, then the greatest value |z| is:
A 36
B 11
C 3 11/+
D 3 11
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Correct answer: 3 11/+
Q164. If ω ≠1 is a cube root of unity, then the value of the expression (1+2ω+2ω2)10 +(2+ω+2ω2)10 + (2+2ω+ω2)10 is
A 0
B 1
C ω
D ω2
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Correct answer: 0
Q165. () θ − θ 4 3 (sin + i cos) is equal to: cos i sin
A cos θ – i sin θ
B cos θ + i sin θ
C sin θ – i cos θ
D sin θ + i cos θ
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Correct answer: cos θ – i sin θ
Q166. If is an imaginary cube root of unity, then the value of– 2 10 2 10 (1 3 3) (3 3) + ω + ω + + ω + ω + ω + ω + + ω + ω + ω + ω + + ω + ω + ω + ω + + ω + ω 2 10 (3 3) + + ω + ω + + ω + ω + + ω + ω + + ω + ω is-
A 0
B 1
C 1
D 2/1
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Correct answer: 0
Q167. If a + ib is a zero of a real polynomial, then the correct statement is–
A ib is also zero
B –ib is also zero
C a is also zero
D a –ib is also zero
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Correct answer: a –ib is also zero
Q168. If x = 3 + i, then the value of the expression x3 – 3x2 –8x+15
A 0
B –15
C 3
D –8
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Correct answer: –15
English UP PCS (Pre) 1998, 2005
Q169. If arg − z 1 π = z +1 4, the locus of z is:
A straight line
B circle
C ellipse
D hyperbola
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Correct answer: circle
Q170. If the complex numbers Z1, Z2, Z3 represent the vertices of an equilateral triangle, such that 1 2 3 Z = Z = Z then the value of Z1 + Z2+Z3 is:
A 1
B –1
C 0
D 3
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Correct answer: 0
Q171. If w is an imaginary cube root of unity, then the common roots of the equations z3 + 2z2 + 2z + 1 = 0 and z1985 + z100 + 1 = 0 are
A 1, w
B w, w2
C 1, w2
D none of the above
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Correct answer: w, w2
Q172. If w is an imaginary cube root of unity and x=a+b, y=aw+bw2, z=aw2 +bw, then x3 +y3 +z3 is equal to
A a3/+ b3
B 0
C 2(a3 + b3)
D 3(a3 + b3)
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Correct answer: 3(a3 + b3)
Q173. If 398 1 i + − =x+iy, then (x, y) is equal to
A (–1,0)
B (1,0)
C (0,–1)
D (0,1)
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Correct answer: (–1,0)
English (GIC) Lecturer 2015
Q174. If z is a purely real number such that Re(z)<0, then arg(z) is equal to
A –π/2
B 0
C π/2
D π
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Correct answer: π
English (GIC) Lecturer, 2015
Q175. The sum of nth roots of unity is
A 0
B 1
C 2
D None of the above
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Correct answer: 0
English (GIC) Lecturer 2015
Q176. Radius of the circle z – 3 = 2 z + 3 is
A 2
B 3
C 4
D 5
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Correct answer: 4
English (GIC) Lecturer 2015
Q177. If 3+4i is a root of the equation x2 +px+q = 0, then
A p = 6, q = 25
B p = 6, q = –15
C p = –6, q = –7
D p = –6, q = 25
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Correct answer: p = –6, q = 25
English (GIC) Lecturer, 2015
Q178. If 1 2 1 2 z 3z 1, 3 z z − = − − 2 z 1, then the value of 1 z is
A 3
B 1/3
C 0
D None of these
Show answer
Correct answer: 3
English (GIC) Lecturer 2015
Q179. If 30 15 3 i 3 3 (A iB), 2 2 then (A,B)
A (0, 1)
B (–1, 0)
C (1, 0)
D (0, –1)
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Correct answer: (–1, 0)
English (GIC) Lecturer 2015
Q180. If n is a positive integer, then– n n 3 i 3 i is equal to –
A n 1 n 2 cos 6
B n n 2 cos 6
C n 1 n 2 cos 6
D None of the above
Show answer
Correct answer: n 1 n 2 cos 6