JEE PYQ: Complex Numbers Question 7
Question 7 - 2021 (18 Mar Shift 1)
Let $z_1, z_2$ be the roots of the equation $z^2 + az + 12 = 0$ and $z_1, z_2$ form an equilateral triangle with origin. Then, the value of $|a|$ is
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Answer: 6
Solution
For equilateral triangle with origin: $z_1^2 + z_2^2 = z_1 z_2$. $(z_1+z_2)^2 - 2z_1z_2 = z_1z_2 \Rightarrow a^2 - 24 = 12 \Rightarrow a^2 = 36 \Rightarrow |a| = 6$.