Q161.If the complex numbers Z1, Z2, Z3 are in arithmetic progression, then they lie on
Correct answer: line
Q162.In the complex plane, the equation − = − 2 z 1 z 2 represents a:
Correct answer: circle
Q163.The equation 2 z z = has:
Correct answer: four solutions
Q164.The point z in Argand's plane moves such that Re iz +1 = 2 iz -1 where z = x+iy, the locus of is:
Correct answer: a circle
Q165.If 2 z - = 6 z, then the greatest value |z| is:
Correct answer: 3 11/+
Q166.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
Correct answer: 0
Q167.() θ − θ 4 3 (sin + i cos) is equal to: cos i sin
Correct answer: cos θ – i sin θ
Q168.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-
Correct answer: 0
Q169.If a + ib is a zero of a real polynomial, then the correct statement is–
Correct answer: a –ib is also zero
Q170.If x = 3 + i, then the value of the expression x3 – 3x2 –8x+15
Correct answer: –15
EnglishUP PCS (Pre) 1998, 2005
Q171.If arg − z 1 π = z +1 4, the locus of z is:
Correct answer: circle
Q172.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:
Correct answer: 0
Q173.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
Correct answer: w, w2
Q174.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
Correct answer: 3(a3 + b3)
Q175.If 398 1 i + − =x+iy, then (x, y) is equal to
Correct answer: (–1,0)
English(GIC) Lecturer 2015
Q176.If z is a purely real number such that Re(z)<0, then arg(z) is equal to
Correct answer: π
English(GIC) Lecturer, 2015
Q177.The sum of nth roots of unity is
Correct answer: 0
English(GIC) Lecturer 2015
Q178.Radius of the circle z – 3 = 2 z + 3 is
Correct answer: 4
English(GIC) Lecturer 2015
Q179.If 3+4i is a root of the equation x2 +px+q = 0, then
Correct answer: p = –6, q = 25
English(GIC) Lecturer, 2015
Q180.If 1 2 1 2 z 3z 1, 3 z z − = − − 2 z 1, then the value of 1 z is
Correct answer: 3