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Saturday, 31 October

JEE Main 2021 · MathsNumerical answerNumerical valueHardMulti-step

JEE Main 26 February 2021, Shift 2, Maths Q82

Question 82 of 90 in this shift, Maths question 22 of 30, Section B.

Let zz be those complex numbers which satisfy ∣z+5∣≤4|z+5| \le 4 and z(1+i)+z‾(1−i)≥−10z(1+i)+\overline{z}(1-i) \ge -10, i=−1i=\sqrt{-1}. If the maximum value of ∣z+1∣2|z+1|^2 is α+β2\alpha+\beta\sqrt{2}, then the value of (α+β)(\alpha+\beta) is __________.

Official answer

48

NTA final key.

Same idea in other shifts

Asked 8× in all
  1. 2 Apr 2026, Shift 2 · Q2Let the circles C1:∣z∣=rC_1: |z| = r and C2:∣z−3−4i∣=5,z∈CeC_2: |z - 3 - 4i| = 5, z \in \mathbb{C}_e be such that C2C_2 lies within C1C_1. If z1z_1 moves on…MediumSingle correct
  2. 2 Apr 2025, Shift 1 · Q2Let zz be a complex number such that ∣z∣=1|z|=1. If 2+k2zk+zˉ=kz\frac{2+k^2z}{k+\bar{z}}=kz, k∈Rk\in\mathbf{R}, then the maximum distance of k+ik2k+ik^2…HardSingle correct
  3. 9 Apr 2024, Shift 2 · Q2Let zz be a complex number such that the real part of z−2iz+2i\frac{z-2i}{z+2i} is zero. Then, the maximum value of ∣z−(6+8i)∣|z-(6+8i)| is equal toMediumSingle correct
  4. 1 Feb 2024, Shift 1 · Q22Let P={z∈C:∣z+2−3i∣≤1}P=\{z\in\mathbb{C}:|z+2-3i|\leq1\} and Q={z∈C:z(1+i)+zˉ(1−i)≤−8}Q=\{z\in\mathbb{C}:z(1+i)+\bar{z}(1-i)\leq-8\}. Let in P∩QP\cap Q, ∣z−3+2i∣|z-3+2i| be maximum and…HardNumerical value
  5. 25 Jul 2022, Shift 2 · Q1For z∈Cz \in \mathbb{C} if the minimum value of (∣z−32∣+∣z−p2i∣)\left(\left|z-3\sqrt{2}\right|+\left|z-p\sqrt{2}i\right|\right) is 525\sqrt{2}, then a…MediumSingle correct
  6. 28 Jul 2022, Shift 1 · Q15Let S1={z1∈C:∣z1−3∣=12}S_1=\left\{z_1\in\mathbf{C}:|z_1-3|=\frac{1}{2}\right\} and S2={z2∈C:∣z2−∣z2+1∣∣=∣z2+∣z2−1∣∣}S_2=\{z_2\in\mathbf{C}:|z_2-|z_2+1||=|z_2+|z_2-1||\}. Then, for…HardSingle correct
  7. 29 Jul 2022, Shift 2 · Q1If z≠0z\neq 0 be a complex number such that ∣z−1z∣=2\left|z-\frac{1}{z}\right|=2, then the maximum value of ∣z∣|z| is :MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.