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← JEE Main 2026 · 4 Apr · Shift 1
MathematicsSingle correct+4 / -1Question 3 of 75

JEE Main 2026 · 4 Apr · Shift 1, Mathematics question 3

Let zz be a complex number such that ∣z+2∣=∣z−2∣|z+2|=|z-2| and arg⁡(z+3z−i)=π4\arg\left(\dfrac{z+3}{z-i}\right)=\dfrac\pi4. Then ∣z∣2|z|^2 is equal to:

Choose one option
Answer and worked solution

Official answer: A

First condition. ∣z+2∣=∣z−2∣|z+2|=|z-2| puts zz on the imaginary axis: z=iyz=iy.

Argument. 3+iyi(y−1)=y−3iy−1\dfrac{3+iy}{i(y-1)}=\dfrac{y-3i}{y-1}. An argument of π4\frac\pi4 needs equal, positive real and imaginary parts: y=−3y=-3, giving 34+34i\frac34+\frac34i ✓.

Value. ∣z∣2=9|z|^2=9.

(A)