JEE Main202229 Jun 2022Morning ShiftMathematicsComplex NumberActual
Let S = z ∈ C : z - 2 ≤ 1 , z 1 + i + z ¯ 1 - i ≤ 2 . Let z - 4 i attains minimum and maximum values, respectively, at z 1 ∈ S and z 2 ∈ S . If 5 z 1 2 + z 2 2 = α + β 5 , where α and β are integers, then the value of α + β is equal to ______.
Correct answer
0
Step-by-step solution
Given z - 2 ≤ 1 x - 2 2 + y 2 ≤ 1           ⋯ i represents interior region of a circle with centre 2 , 0 and radius 1 Now z 1 + i + z ¯ 1 - i ≤ 2 Puting z = x + i y , we get x + i y 1 + i + x - i y 1 - i ≤ 2 ⇒ x - y + i x + y + x - y - i x + y ≤ 2 ∴   x - y ≤ 1         … i Let A 1 , 0 and B 2 , 1 be the points on the line x - y = 1 and the circle x - 2 2 + y 2 = 1 z - 4 i represents the distance from P