JEE Questions for Maths Complex Numbers Quiz 3 - MCQExams.com

The value of (1+ √3i )4 + (1 - √3i)4 is
  • -16
  • 16
  • 14
  • -14
If the fourth roots of unity are z1, z2 , z3 and z4 , then z21 + z22 + z23 + z24 is equal to
  • 0
  • 2
  • 3
  • None of these

Maths-Complex Numbers-14704.png
  • (- 3,
  • (0, 3)
  • (0, -

  • Maths-Complex Numbers-14705.png
If ω # 1 is a cube root of unity, then the sum of the series S = 1+ 2ω+ 3ω2 + • • • + 3ω3n-1 is

  • Maths-Complex Numbers-14707.png
  • 3n(ω - 1)

  • Maths-Complex Numbers-14708.png
  • 0

Maths-Complex Numbers-14710.png
  • cos nθ - i sin nθ
  • cos nθ + i sin nθ
  • cos 2nθ - i sin 2nθ
  • cos 2nθ + i sin 2nθ
If z = cos θ + i sin θ, then the value of
Maths-Complex Numbers-14712.png

  • Maths-Complex Numbers-14713.png
  • 2)
    Maths-Complex Numbers-14714.png

  • Maths-Complex Numbers-14715.png

  • Maths-Complex Numbers-14716.png
If a is a complex number satisfying the equation α2 + α + 1= 0, then α31 is equal to
  • α
  • α2
  • 1
  • i
The smallest positive integral value of n such that
Maths-Complex Numbers-14719.png
  • 4
  • 3
  • 2
  • 8
If n is a positive integer, then (1+ i√3)n + (1 - i√3)n is equal to
  • 2n-1 cos nπ/3
  • 2n cos nπ/3
  • 2n+1 cos nπ/3
  • None of these
If n is an integer which leaves remainder one when divided by three, then (1+ √3i)n + (1- √3i)nn equals
  • - 2n+1
  • 2n+1
  • -(-2)n
  • - 2n
The expression
Maths-Complex Numbers-14723.png
  • nπ + α
  • 2nπ
  • nπ/2 + α
  • None of these
If z2 + z + 1= 0, where z is a complex number, then then the value of
Maths-Complex Numbers-14725.png
  • 6
  • 12
  • 18
  • 24

Maths-Complex Numbers-14727.png
  • n cos ∅
  • cos n∅
  • n cos (n∅/2)
  • sin (n∅/2)
If square root of -7 + 24i is x + iy then x is equal to
  • ± 1
  • ± 2
  • ± 3
  • ± 4
If is a complex cube root of unity, then
Maths-Complex Numbers-14730.png
  • 1/√2
  • 1/2
  • 1
  • √3/2
The value of
Maths-Complex Numbers-14732.png
  • 0
  • -1
  • i
  • 1
If ω is an imaginary cube root of unity and x = a + b, y = aω + bω2, z = aω2 + bω, then x2 + y2 + z2 is equal to
  • 6ab
  • 3ab
  • 6a2b2
  • 3a2b2

Maths-Complex Numbers-14735.png
  • 1
  • √2
  • 2√2
  • 4
  • 8
If ω is a cube root of unity then the value of (1 - ω + ω2 )5 + (1 - ω - ω2)5 is
  • 30
  • 32
  • 2
  • None of these
The principal amplitude of (sin 40o + i cos 40o)5 is
  • 700
  • -1100
  • 1100
  • -700
The modulus and amplitude of (1+ i√3 )8 are respectively
  • 256 and π/3
  • 256 and 2π/3
  • 256 and 2π/3
  • 256 and 8π/3
If 2x = -1+ √3i, then the value of (1- x2 + x)6 - (1- x + x2)6 is
  • 32
  • -64
  • 64
  • 0
The square roots of - 7 - 24√-1 are
  • ± (4 + 3√-1)
  • ±(3 + 4√-
  • ±(3 - 4√-1)
  • ±(4 - 3√-
If 1, ω and ω2 are the cube roots of unity, then , is equal to (1+ω) (1+ ω2) (1 + ω)4 (1+ ω8) is equal to
  • 1
  • 0
  • ω2
  • ω

Maths-Complex Numbers-14742.png

  • Maths-Complex Numbers-14743.png
  • 2)
    Maths-Complex Numbers-14744.png
  • (x + y + z)i
  • π

  • Maths-Complex Numbers-14745.png
If 1 + x2 =√3x then
Maths-Complex Numbers-14747.png
  • 0
  • 48
  • -24
  • 24
  • -48
If ω (#is a cube root of unity and (1+ ω2 )n = (1+ ω4 )n , then the least positive value of n is
  • 2
  • 3
  • 5
  • 6

Maths-Complex Numbers-14750.png
  • 0
  • 1
  • - 1
  • None of these

Maths-Complex Numbers-14752.png
  • 1
  • 0
  • - 1
  • None of these
A value of n such that
Maths-Complex Numbers-14754.png
  • 12
  • 3
  • 2
  • 1
If 1, ω and ω2 are the cube roots of unity, then (1 - ω + ω2)(1 - ω2 + ω4)(1 - ω4 + ω)8 (1 - ω8 + ω16) ... up to 2n factors is
  • 2n
  • 22n
  • 1
  • - 22n
If 1, a1, a2,...an-1 are the nth roots of unity, then the value of (1-a1) (1 - a2)(1 - a3)...(1 - an-1) is
  • √3
  • 1/2
  • n
  • 0
One root of (1)1/3 is

  • Maths-Complex Numbers-14758.png
  • 2)
    Maths-Complex Numbers-14759.png

  • Maths-Complex Numbers-14760.png

  • Maths-Complex Numbers-14761.png
If iz4 + 1 = 0, then z can take the value

  • Maths-Complex Numbers-14763.png
  • cos π/8 + i sin π/8
  • 1/4i
  • i
If i = √-1, then
Maths-Complex Numbers-14765.png
  • 1 - i√-3
  • -1 + i√-3
  • i√3
  • -i√3
  • 1 + i√3
If a = e i(2π/3) , then the equation whose roots are a + a-2 and a2 + a -4 is
  • x2 -2x + 4 = 0
  • x2 - x + 1 = 0
  • x2 + x + 4 = 0
  • x2 + 2x - 4 = 0
  • x2 + 2x + 4 = 0

Maths-Complex Numbers-14768.png
  • 2
  • zero
  • - 1
  • 1
If ω is an imaginary cube root of unity, then (1+ ω - ω2)7 equals
  • 128ω
  • -128ω
  • 128ω2
  • - 128ω2

Maths-Complex Numbers-14770.png
  • 16
  • -16
  • 16ω
  • 16ω2

Maths-Complex Numbers-14772.png
  • 0
  • - 1
  • 1
  • i
The minimum value of |a + bω + cω2|, where a, b and c are all not equal integers and ω(≠1)is a cube root of unity, is
  • √3
  • 1/2
  • 1
  • 0

Maths-Complex Numbers-14775.png
  • 1
  • ω
  • ω2
  • 0

Maths-Complex Numbers-14777.png
  • 1 but not 1
  • -1 but not 1
  • +1 or -1
  • 0

Maths-Complex Numbers-14779.png
  • 27
  • 27i
  • 214 i
  • - 27 i
  • -2 14
If 1, ω and ω2 are the cube roots of unity, then ω(1+ ω)3 — (1+ ω2 ) is equal to
  • 1
  • - 1
  • i
  • 0
If x = α + β, y = αω + βω2, z = aω2 +βω, βω is an imaginary cube root of unity. Then, the value of xyz is
  • α2 + β2
  • α2 - β2
  • α 3 + β3
  • α3 - β3
Which of the following is a fourth root of 1/2 + i √3/2 ?
  • cos π/12
  • cos π/2
  • cos π/6
  • cos π/3
If 1, ω and ω2 are the cube roots of unity, (3 + ω24)6 is equal to
  • 64
  • 729
  • 2
  • 0
Let complex numbers a and 1/a lie on circles (x —x0)2 +(y —y0)2 = r2 and (x - x0 )2 ( y - y0)2 4r2, respectively. If z0 = x0 + iy0 satisfies the equation 2|z0|2 = r2+ 2, then |a|is equal to
  • 1/√2
  • 1/2
  • 1/√7
  • 1/3
If z is a complex such that |z| ≥ 2, then the minimum value of |z + 1/2|
  • (a) is equal to 5/2
  • (b) lies in the interval (1, 2)
  • (c) is strictly greater than 5/2
  • (d) is strictly greater than 3/2 but less than 5/2
0:0:1


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