# Chapter 2: Complex Numbers - Online Test

Q1. If | z1 | = 1, | z2 | = 2, | z3 | = 3 and | 9z1 z2 + 4z1 z3 + z2 z3 | = 12 , then the value of | z1 + z2 + z3 | is
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Q2. If z is a complex number such that z C \R and z + 1/z R , then | z | is
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Q3. z1 , z3 , and z3 are complex numbers such that z1 + z2 + z3 = 0 and | z1 | =| z2 | =| z3 | = 1 then z 2 + z 2 + z 2 is
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Q4. If (z-1) / (z+1), is purely imaginary, then | z | is
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Q5. If z = x + iy is a complex number such that | z + 2 | = | z 2 | , then the locus of z is
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Q6. The principal argument of 3/(-1+i ) is
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Q7. The principal argument of (sin 40°+ i cos 40°)is
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Q8. If (1+ i) (1+ 2i) (1+ 3i)L(1+ ni) = x + iy , then 2 5 10L(1+ n2 ) is
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Q9. If ω 1 is a cubic root of unity and (1+ ω)7 = A + Bω , then ( A, B) equals
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Q10. The principal argument of the complex number  is
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