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NDA 2 2024 Maths, question 41

Topic: Algebra

Passage · Q41 to Q42

Let Z1Z_{1} and Z2Z_{2} be any two complex numbers such that Z12+Z22+Z1Z2=0Z_{1}^{2}+Z_{2}^{2}+Z_{1}Z_{2}=0.

Q41

What is the value of ∣Z1Z2∣\left| \frac{Z_{1}}{Z_{2}} \right|?

  1. (a) 11Correct answer
  2. (b) 22
  3. (c) 33
  4. (d) 44

Solution.

Answer: (a) 11

  1. The requested ratio requires Z₂≠0.
  2. Dividing the equation by Z₂² gives w²+w+1=0, where w=Z₁/Z₂.
  3. Thus w=(−1±i√3)/2 and |w|=1.
  4. The pair Z₁=Z₂=0 satisfies the shared equation but is excluded by the displayed ratio's domain.