Complex Numbers
Complex Numbers
star_batch_jee_advanced_2025
Grade 11

Question:

$w_1, w_2$ be roots of $(a+\bar{c})z^2 + (b+\bar{b})z + (\bar{a}+c) = 0$. If $|z_1| < |z_2| < 1$, then
$|w_1| < 1$
$|w_1| = 1$
$|w_2| < 1$
$|w_2| = 1$

Step-by-Step Solution

Key Concept: The quadratic equation $(a+\bar{c})z^2 + (b+\bar{b})z + (\bar{a}+c) = 0$ has a special structure where coefficients satisfy a conjugate reciprocal relationship: if we denote the equation as $Az^2 + Bz + C = 0$, then $C = \bar{A}$, making it a self-reciprocal equation. This means if $w$ is a root, then $\frac{1}{\bar{w}}$ is also a root, implying $|w_1| \cdot |w_2| = 1$.
For a triangle with sides $a, a, b$, the triangle inequality requires $2a > b$, so $b b$ to constrain possible side lengths and count systematically by ranges.
Correct Answer: 2,4

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