Question:

If \(Z_1\ne 0\) and \(Z_2\) be two complex numbers such that \(\frac{Z_2}{Z_1}\) is a purely imaginary number, then \(\left|\frac{2Z_1+3Z_2}{2Z_1-3Z_2}\right|\) is equal to :

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Write \(Z_2=ikZ_1\) with k real and compare the moduli of numerator and denominator.
Updated On: Oct 31, 2026
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The Correct Option is D

Solution and Explanation

Since \(\frac{Z_2}{Z_1}\) is purely imaginary, let \(\frac{Z_2}{Z_1}=ik\) with k real.
Then \(\frac{2Z_1+3Z_2}{2Z_1-3Z_2}=\frac{2+3ik}{2-3ik}\).
The numerator and denominator are complex conjugates, so they have equal modulus.
\(\left|\frac{2+3ik}{2-3ik}\right|=\frac{\sqrt{4+9k^2}}{\sqrt{4+9k^2}}=1\).
Answer: (4) 1
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