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Let `z_(1)` and `z_(2)` be any two non-zero complex numbers such that `3|z_(1)|=2|z_(2)|. "If "z=(3z_(1))/(2z_(2)) + (2z_(2))/(3z_(1))`, then

A

`|z| = (1)/(2) sqrt((17)/(2))`

B

Re(z) = 0

C

`|z| = sqrt((5)/(2))`

D

Im(z) = 0

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The correct Answer is:
To solve the problem, we need to analyze the expression given for \( z \) and the condition involving the complex numbers \( z_1 \) and \( z_2 \). ### Step-by-Step Solution: 1. **Given Condition**: We have the condition \( 3|z_1| = 2|z_2| \). This can be rewritten as: \[ \frac{|z_1|}{|z_2|} = \frac{2}{3} \] 2. **Expression for \( z \)**: We need to evaluate: \[ z = \frac{3z_1}{2z_2} + \frac{2z_2}{3z_1} \] 3. **Let \( a = \frac{3z_1}{2z_2} \)**: From the condition, we can find the modulus of \( a \): \[ |a| = \left| \frac{3z_1}{2z_2} \right| = \frac{3|z_1|}{2|z_2|} = \frac{3 \cdot \frac{2}{3}|z_2|}{2|z_2|} = 1 \] Thus, \( |a| = 1 \). 4. **Finding \( \frac{2z_2}{3z_1} \)**: We can express \( \frac{2z_2}{3z_1} \) in terms of \( a \): \[ \frac{2z_2}{3z_1} = \frac{1}{a} \] 5. **Substituting back into \( z \)**: Now substituting \( a \) and \( \frac{1}{a} \) into the expression for \( z \): \[ z = a + \frac{1}{a} \] 6. **Using Polar Form**: Since \( |a| = 1 \), we can express \( a \) in polar form: \[ a = e^{i\theta} = \cos\theta + i\sin\theta \] Therefore, \[ \frac{1}{a} = e^{-i\theta} = \cos\theta - i\sin\theta \] 7. **Adding the two expressions**: Now, we compute: \[ z = (\cos\theta + i\sin\theta) + (\cos\theta - i\sin\theta) = 2\cos\theta \] The imaginary parts cancel out, leaving us with a real number. 8. **Conclusion**: Since \( z \) is a real number, the imaginary part of \( z \) is zero. Therefore, we conclude that: \[ \text{Imaginary part of } z = 0 \] ### Final Answer: The imaginary part of \( z \) is zero.
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